Transmission of material in this release is embargoed until
8:30 a.m. (EDT) Tuesday, October 16, 2012 USDL-12-2070
Technical information: (202) 691-7000 Reed.Steve@bls.gov www.bls.gov/cpi
Media Contact: (202) 691-5902 PressOffice@bls.gov
Consumer Price Index - September 2012
The Consumer Price Index for All Urban Consumers (CPI-U) increased
0.6 percent in September on a seasonally adjusted basis, the U.S.
Bureau of Labor Statistics reported today. Over the last 12 months,
the all items index increased 2.0 percent before seasonal adjustment.
For the second month in a row, the substantial increase in the all
items index was mostly the result of an increase in the gasoline
index, which rose 7.0 percent in September after increasing 9.0
percent in August. The other major energy indexes increased in
September as well.
The food index increased 0.1 percent in September; the index for food
at home was unchanged as major grocery store food indexes continue to
be mixed. The index for all items less food and energy rose 0.1
percent for the third month in a row. Indexes for shelter, medical
care, apparel, and airline fares were among those that increased,
while the indexes for used cars and trucks, new vehicles, personal
care, and household furnishings and operations all declined.
The 12-month change in the index for all items was 2.0 percent in
September, an increase from the August figure of 1.7 percent and the
highest since April. The index for all items less food and energy
also rose 2.0 percent for the 12 months ending September; the food
index has increased 1.6 percent and the energy index has risen 2.3
percent over that span.
Table A. Percent changes in CPI for All Urban Consumers (CPI-U): U.S. city
average
Seasonally adjusted changes from
preceding month
Un-
adjusted
12-mos.
Mar. Apr. May June July Aug. Sep. ended
2012 2012 2012 2012 2012 2012 2012 Sep.
2012
All items.................. .3 .0 -.3 .0 .0 .6 .6 2.0
Food...................... .2 .2 .0 .2 .1 .2 .1 1.6
Food at home............. .1 .2 -.1 .1 .0 .1 .0 .8
Food away from home (1).. .2 .3 .2 .2 .2 .3 .2 2.8
Energy.................... .9 -1.7 -4.3 -1.4 -.3 5.6 4.5 2.3
Energy commodities....... 1.7 -2.6 -6.4 -2.3 .2 8.6 6.7 6.4
Gasoline (all types).... 1.7 -2.6 -6.8 -2.0 .3 9.0 7.0 6.8
Fuel oil (1)............ 2.7 -1.1 -2.8 -7.9 -.5 4.6 4.1 4.0
Energy services.......... -.4 -.2 -.7 .0 -1.1 .8 .7 -3.8
Electricity............. -.8 .2 .3 -.5 -1.3 .2 .2 -1.5
Utility (piped) gas
service.............. .9 -1.8 -4.1 1.7 -.2 2.8 2.0 -10.7
All items less food and
energy................. .2 .2 .2 .2 .1 .1 .1 2.0
Commodities less food and
energy commodities.... .2 .2 .2 .2 .0 -.2 -.2 .7
New vehicles............ .2 .4 .2 .2 -.1 .2 -.1 1.0
Used cars and trucks.... 1.3 1.5 1.0 .0 -.5 -.9 -1.4 -1.6
Apparel................. .5 .4 .4 .5 .2 -.5 .3 2.7
Medical care commodities
(1).................. .4 .0 .0 .1 .5 .3 -.1 3.3
Services less energy
services.............. .2 .3 .2 .2 .1 .1 .3 2.5
Shelter................. .2 .2 .2 .1 .1 .2 .2 2.2
Transportation services .3 .5 .3 -.2 -.2 .0 .5 1.5
Medical care services... .3 .4 .5 .7 .3 .2 .4 4.4
1 Not seasonally adjusted.
Consumer Price Index Data for September 2012
Food
The food index rose 0.1 percent in September after a 0.2 percent
increase in August. The index for food at home was unchanged in
September after rising 0.1 percent the previous month. Among major
grocery store food groups, the largest increase in September was in
the index for nonalcoholic beverages, which rose 0.9 percent in
September after declining in July and August. The indexes for dairy
and related products and for other food at home also rose in
September. The largest decline was for the index for meats, poultry,
fish, and eggs, which fell 0.6 percent after rising in each of the
three previous months. Also declining was the index for fruits and
vegetables, which fell 0.4 percent as the fresh fruits index declined
0.9 percent. The index for cereals and bakery products fell 0.1
percent. The index for food at home has risen 0.8 percent over the
last 12 months, the smallest figure since August 2010. The index for
food away from home increased 0.2 percent in September and has risen
2.8 percent over the last 12 months.
Energy
The energy index rose 4.5 percent in September after a 5.6 percent
increase in August. The gasoline index increased 7.0 percent in
September, its third straight increase. (Before seasonal adjustment,
gasoline prices increased 4.1 percent in September.) Other energy
indexes had increases similar to August: The fuel oil index increased
4.1 percent in September after rising 4.6 percent in August; the
index for natural gas rose 2.0 percent in September following a 2.8
percent August increase; and the electricity index repeated its
August increase of 0.2 percent. Over the last 12 months, the energy
index has risen 2.3 percent (the August 12-month change was a 0.6
percent decline). The gasoline index has risen 6.8 percent over the
last 12 months, and the index for fuel oil has increased 4.0 percent.
In contrast, the index for natural gas has fallen 10.7 percent and
the electricity index has declined 1.5 percent.
All items less food and energy
The index for all items less food and energy increased 0.1 percent in
September, the same increase as in July and August. The index for
shelter repeated its August increase of 0.2 percent, with the rent
index rising 0.3 percent and the index for owners' equivalent rent
increasing 0.2 percent. The medical care index rose 0.3 percent in
September, with the hospital services index rising 0.6 percent. The
index for airline fares rose 1.4 percent in September after declining
in each of the three previous months. The apparel index turned up in
September, rising 0.3 percent after declining 0.5 percent in August.
Similarly, the tobacco index rose 0.2 percent in September after an
August decline. In contrast to these increases, the index for used
cars and trucks posted its largest decline since February 2009,
falling 1.4 percent. The index for new vehicles turned down in
September, decreasing 0.1 percent after increasing 0.2 percent in
August. The indexes for household furnishings and operations and
personal care also declined in September.
The index for all items less food and energy has risen 2.0 percent
over the last 12 months, a slight increase from the August figure of
1.9 percent. The index for medical care has risen 4.1 percent over
that span, the apparel index has increased 2.7 percent and the
shelter index rose 2.2 percent. The index for airline fares declined
2.6 percent over the last 12 months and the index for used cars and
trucks fell 1.6 percent.
Not seasonally adjusted CPI measures
The Consumer Price Index for All Urban Consumers (CPI-U) increased
2.0 percent over the last 12 months to an index level of 231.407
(1982-84=100). For the month, the index increased 0.4 percent prior
to seasonal adjustment.
The Consumer Price Index for Urban Wage Earners and Clerical Workers
(CPI-W) increased 2.0 percent over the last 12 months to an index
level of 228.184 (1982-84=100). For the month, the index increased
0.5 percent prior to seasonal adjustment.
The Chained Consumer Price Index for All Urban Consumers (C-CPI-U)
increased 1.7 percent over the last 12 months. For the month, the
index increased 0.4 percent on a not seasonally adjusted basis.
Please note that the indexes for the post-2010 period are subject to
revision.
The Consumer Price Index for October 2012 is scheduled to be released
on Thursday, November 15, 2012, at 8:30 a.m. (EST).
Facilities for Sensory Impaired
Information from this release will be made available to sensory
impaired individuals upon request. Voice phone: 202-691-5200,
Federal Relay Services: 1-800-877-8339.
Brief Explanation of the CPI
The Consumer Price Index (CPI) is a measure of the average change in
prices over time of goods and services purchased by households. The
Bureau of Labor Statistics publishes CPIs for two population groups:
(1) the CPI for Urban Wage Earners and Clerical Workers (CPI-W), which
covers households of wage earners and clerical workers that comprise
approximately 29 percent of the total population and (2) the CPI for
All Urban Consumers (CPI-U) and the Chained CPI for All Urban
Consumers (C-CPI-U), which cover approximately 88 percent of the total
population and include in addition to wage earners and clerical worker
households, groups such as professional, managerial, and technical
workers, the self-employed, short-term workers, the unemployed, and
retirees and others not in the labor force.
The CPIs are based on prices of food, clothing, shelter, and fuels,
transportation fares, charges for doctors' and dentists' services,
drugs, and other goods and services that people buy for day-to-day
living. Prices are collected each month in 87 urban areas across the
country from about 4,000 housing units and approximately 26,000 retail
establishments-department stores, supermarkets, hospitals, filling
stations, and other types of stores and service establishments. All
taxes directly associated with the purchase and use of items are
included in the index. Prices of fuels and a few other items are
obtained every month in all 87 locations. Prices of most other
commodities and services are collected every month in the three
largest geographic areas and every other month in other areas. Prices
of most goods and services are obtained by personal visits or
telephone calls of the Bureau's trained representatives.
In calculating the index, price changes for the various items in each
location are averaged together with weights, which represent their
importance in the spending of the appropriate population group. Local
data are then combined to obtain a U.S. city average. For the CPI-U
and CPI-W separate indexes are also published by size of city, by
region of the country, for cross-classifications of regions and
population-size classes, and for 27 local areas. Area indexes do not
measure differences in the level of prices among cities; they only
measure the average change in prices for each area since the base
period. For the C-CPI-U data are issued only at the national level.
It is important to note that the CPI-U and CPI-W are considered final
when released, but the C-CPI-U is issued in preliminary form and
subject to two annual revisions.
The index measures price change from a designed reference date. For
the CPI-U and the CPI-W the reference base is 1982-84 equals 100. The
reference base for the C-CPI-U is December 1999 equals 100. An
increase of 16.5 percent from the reference base, for example, is
shown as 116.500. This change can also be expressed in dollars as
follows: the price of a base period market basket of goods and
services in the CPI has risen from $10 in 1982-84 to $11.65.
For further details visit the CPI home page on the Internet at
http://www.bls.gov/cpi/ or contact our CPI Information and Analysis
Section on (202) 691-7000.
Note on Sampling Error in the Consumer Price Index
The CPI is a statistical estimate that is subject to sampling error
because it is based upon a sample of retail prices and not the
complete universe of all prices. BLS calculates and publishes
estimates of the 1-month, 2-month, 6-month and 12-month percent change
standard errors annually, for the CPI-U. These standard error
estimates can be used to construct confidence intervals for hypothesis
testing. For example, the estimated standard error of the 1 month
percent change is 0.03 percent for the U.S. All Items Consumer Price
Index. This means that if we repeatedly sample from the universe of
all retail prices using the same methodology, and estimate a
percentage change for each sample, then 95% of these estimates would
be within 0.06 percent of the 1 month percentage change based on all
retail prices. For example, for a 1-month change of 0.2 percent in
the All Items CPI for All Urban Consumers, we are 95 percent confident
that the actual percent change based on all retail prices would fall
between 0.14 and 0.26 percent. For the latest data, including
information on how to use the estimates of standard error, see
"Variance Estimates for Price Changes in the Consumer Price Index,
January-December 2011". These data are available on the CPI home page
(http://www.bls.gov/cpi), or by using the following link
http://www.bls.gov/cpi/cpivar2011.pdf
Calculating Index Changes
Movements of the indexes from one month to another are usually
expressed as percent changes rather than changes in index points,
because index point changes are affected by the level of the index in
relation to its base period while percent changes are not. The
example below illustrates the computation of index point and percent
changes.
Percent changes for 3-month and 6-month periods are expressed as
annual rates and are computed according to the standard formula for
compound growth rates. These data indicate what the percent change
would be if the current rate were maintained for a 12-month period.
Index Point Change
CPI
202.416
Less previous index
201.800
Equals index point change
.616
Percent Change
Index point difference
.616
Divided by the previous index
201.800
Equals
0.003
Results multiplied by one hundred
0.003x100
Equals percent change
0.3
Regions Defined
The states in the four regions are listed below.
The Northeast--Connecticut, Maine, Massachusetts, New Hampshire, New
York, New Jersey, Pennsylvania, Rhode Island, and Vermont.
The Midwest--Illinois, Indiana, Iowa, Kansas, Michigan, Minnesota,
Missouri, Nebraska, North Dakota, Ohio, South Dakota, and Wisconsin.
The South--Alabama, Arkansas, Delaware, Florida, Georgia, Kentucky,
Louisiana, Maryland, Mississippi, North Carolina, Oklahoma, South
Carolina, Tennessee, Texas, Virginia, West Virginia, and the District
of Columbia.
The West--Alaska, Arizona, California, Colorado, Hawaii, Idaho,
Montana, Nevada, New Mexico, Oregon, Utah, Washington, and Wyoming.
A Note on Seasonally Adjusted and Unadjusted Data
Because price data are used for different purposes by different
groups, the Bureau of Labor Statistics publishes seasonally adjusted
as well as unadjusted changes each month.
For analyzing general price trends in the economy, seasonally adjusted
changes are usually preferred since they eliminate the effect of
changes that normally occur at the same time and in about the same
magnitude every year--such as price movements resulting from changing
climatic conditions, production cycles, model changeovers, holidays,
and sales.
The unadjusted data are of primary interest to consumers concerned
about the prices they actually pay. Unadjusted data also are used
extensively for escalation purposes. Many collective bargaining
contract agreements and pension plans, for example, tie compensation
changes to the Consumer Price Index before adjustment for seasonal
variation.
Seasonal factors used in computing the seasonally adjusted indexes are
derived by the X-12-ARIMA Seasonal Adjustment Method. Seasonally
adjusted indexes and seasonal factors are computed annually. Each
year, the last 5 years of seasonally adjusted data are revised. Data
from January 2007 through December 2011 were replaced in January 2012.
Exceptions to the usual revision schedule were: the updated seasonal
data at the end of 1977 replaced data from 1967 through 1977; and, in
January 2002, dependently seasonally adjusted series were revised for
January 1987-December 2001 as a result of a change in the aggregation
weights for dependently adjusted series. For further information,
please see "Aggregation of Dependently Adjusted Seasonally Adjusted
Series," in the October 2001 issue of the CPI Detailed Report.
Effective with the publication of data from January 2006 through
December 2010 in January 2011, the Video and audio series and the
Information technology, hardware and services series were changed from
independently adjusted to dependently adjusted. This resulted in an
increase in the number of seasonal components used in deriving
seasonal movement of the All items and 54 other lower level
aggregations, from 73 for the publication of January 1998 through
December 2005 data to 82 for the publication of seasonally adjusted
data for January 2006 and later. Each year the seasonal status of
every series is reevaluated based upon certain statistical criteria.
If any of the 82 components change their seasonal adjustment status
from seasonally adjusted to not seasonally adjusted, not seasonally
adjusted data will be used in the aggregation of the dependent series
for the last 5 years, but the seasonally adjusted indexes before that
period will not be changed. Note: 38 of the 82 components are not
seasonally adjusted for 2012.
Seasonally adjusted data, including the all items index levels, are
subject to revision for up to five years after their original release.
For this reason, BLS advises against the use of these data in
escalation agreements.
Effective with the calculation of the seasonal factors for 1990, the
Bureau of Labor Statistics has used an enhanced seasonal adjustment
procedure called Intervention Analysis Seasonal Adjustment for some
CPI series. Intervention Analysis Seasonal Adjustment allows for
better estimates of seasonally adjusted data. Extreme values and/or
sharp movements which might distort the seasonal pattern are estimated
and removed from the data prior to calculation of seasonal factors.
Beginning with the calculation of seasonal factors for 1996, X-12-
ARIMA software was used for Intervention Analysis Seasonal Adjustment.
For the seasonal factors introduced in January 2012, BLS adjusted 31
series using Intervention Analysis Seasonal Adjustment, including
selected food and beverage items, motor fuels, electricity and
vehicles. For example, this procedure was used for the Motor fuel
series to offset the effects of events such as damage to oil
refineries from Hurricane Katrina.
For a complete list of Intervention Analysis Seasonal Adjustment
series and explanations, please refer to the article "Intervention
Analysis Seasonal Adjustment", located on our website at
http://www.bls.gov/cpi/cpisapage.htm.
For additional information on seasonal adjustment in the CPI, please
write to the Bureau of Labor Statistics, Division of Consumer Prices
and Price Indexes, Washington, DC 20212 or contact David Levin at
(202) 691-6968, or by e-mail at Levin.David@bls.gov. If you have
general questions about the CPI, please call our information staff at
(202) 691-7000.
