The Consumer Price Index for All Urban Consumers (CPI-U) in the Chicago-Gary-Kenosha area rose 0.4 percent in September, the U.S. Bureau of Labor Statistics reported today. Assistant Commissioner for Regional Operations Charlene Peiffer noted that in September the food index edged down 0.1 percent and the energy index increased 2.2 percent. The all items less food and energy index rose 0.4 percent over the month. Among the indexes within the all items less food and energy category, prices were higher for shelter and apparel. (Data in this report are not seasonally adjusted. Accordingly, month-to-month changes may reflect the impact of seasonal influences.)

Over the last 12 months, the Chicago area all items CPI-U increased 2.1 percent. (See chart 1 and table A.) Over the year the food index increased 1.3 percent and energy costs rose 7.6 percent. Energy costs rose primarily due to an increase in gasoline prices. The all items less food and energy index was 1.8 percent higher over the year. (See table 1.)

Food

Food prices edged down 0.1 percent in September. The food at home index (groceries) fell 0.4 percent, while the food away from home (restaurant, cafeteria, and vending purchases) index rose 0.3 percent. Within the food at home group, prices were lower in September for carbonated drinks, pork chops, and potatoes. In contrast, the indexes for other fresh vegetables, uncooked ground beef, and uncooked beef roasts were higher.

From September 2016 to September 2017, the food index increased 1.3 percent. Grocery prices rose 0.9 percent, while food away from home prices rose 1.9 percent over the year.

Energy

The energy index advanced 2.2 percent in September, primarily due to a 5.5-percent increase in gasoline prices. Electricity costs rose 0.2 percent over the month. In contrast, utility (piped) gas service costs fell 1.8 percent.

Over the year, the Chicago area energy index rose 7.6 percent. From September 2016 to September 2017 gasoline prices increased 11.6 percent. Costs for electricity and utility (piped) gas service were up 6.8 percent and 0.3 percent, respectively over the year.

All items less food and energy

The index for all items less food and energy rose 0.4 percent in September. Among the index’s components, prices were higher for shelter (0.6 percent) and apparel (4.3 percent).

Over the year, the index for all items less food and energy increased 1.8 percent. Increases in the indexes for shelter (2.2 percent), recreation (7.6 percent), and medical care (4.2 percent) were major contributing factors.

Table A. Chicago CPI-U 1-month and 12-month percent changes, all items index, not seasonally adjusted

Month	2013		2014		2015		2016		2017
	1-month	12-month	1-month	12-month	1-month	12-month	1-month	12-month	1-month	12-month
January	0.2	1.2	0.9	1.2	-0.2	0.4	0.8	0.9	0.7	1.8
February	1.1	2.3	0.5	0.7	0.0	-0.2	-0.2	0.7	0.1	2.2
March	-0.1	0.9	1.1	1.9	0.7	-0.6	0.1	0.2	-0.1	2.0
April	0.0	0.9	0.5	2.4	0.1	-0.9	0.6	0.7	0.4	1.7
May	0.5	1.5	-0.1	1.8	0.3	-0.5	0.0	0.3	0.2	1.8
June	0.1	1.7	0.4	2.0	0.2	-0.7	0.5	0.7	0.0	1.3
July	-0.2	1.7	-0.4	1.9	-0.1	-0.5	-0.8	-0.1	0.0	2.2
August	0.1	1.1	0.1	1.9	0.4	-0.1	0.2	-0.2	0.3	2.3
September	-0.2	0.7	0.0	2.1	-0.3	-0.4	0.6	0.6	0.4	2.1
October	-0.3	0.5	-0.4	2.0	-0.1	-0.2	0.1	0.8
November	-0.3	0.6	-0.8	1.6	-0.4	0.2	0.2	1.5
December	-0.3	0.5	-0.4	1.5	-0.6	0.0	-0.2	1.9

The October 2017 Consumer Price Index for Chicago is scheduled to be released on Wednesday, November 15, 2017.

Technical Note

The Consumer Price Index (CPI) is a measure of the average change in prices over time in a fixed market basket of goods and services. The Bureau of Labor Statistics publishes CPIs for two population groups: (1) a CPI for All Urban Consumers (CPI-U) which covers approximately 89 percent of the total population and (2) a CPI for Urban Wage Earners and Clerical Workers (CPI-W) which covers 28 percent of the total population. The CPI-U includes, in addition to wage earners and clerical workers, 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 CPI is based on prices of food, clothing, shelter, and fuels, transportation fares, charges for doctors' and dentists' services, drugs, and the other goods and services that people buy for day-to-day living. Each month, prices are collected in 87 urban areas across the country from about 6,000 housing units and approximately 24,000 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.

The index measures price changes from a designated reference date (1982-84) that equals 100.0. An increase of 16.5 percent, for example, is shown as 116.5. 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 see the CPI home page on the Internet at www.bls.gov/cpi and the BLS Handbook of Methods, Chapter 17, The Consumer Price Index, available on the Internet at www.bls.gov/opub/hom/pdf/homch17.pdf.

In calculating the index, price changes for the various items in each location are averaged together with weights that represent their importance in the spending of the appropriate population group. Local data are then combined to obtain a U.S. city average. Because the sample size of a local area is smaller, the local area index is subject to substantially more sampling and other measurement error than the national index. In addition, local indexes are not adjusted for seasonal influences. As a result, local area indexes show greater volatility than the national index, although their long-term trends are quite similar. Note: Area indexes do not measure differences in the level of prices between cities; they only measure the average change in prices for each area since the base period.

The Chicago-Gary-Kenosha, Ill.-Ind.-Wis. consolidated area covered in this release is comprised of Cook, DeKalb, DuPage, Grundy, Kane, Kankakee, Kendall, Lake, McHenry, and Will Counties in Illinois; Lake and Porter Counties in Indiana; and Kenosha County in Wisconsin.

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