The Consumer Price Index for All Urban Consumers (CPI-U) in the Chicago-Naperville-Elgin area rose 0.4 percent in May, the U.S. Bureau of Labor Statistics reported today. Assistant Commissioner for Regional Operations Charlene Peiffer noted that the energy index increased 4.9 percent while food prices were unchanged in May. The all items less food and energy index edged up 0.1 percent over the month. Within the all items less food and energy category, prices were higher for shelter and medical care. The apparel index was lower over the month. (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 2.3 percent. (See chart 1 and table A.) Over the year, the energy index rose 13.2 percent. The rise in the energy index was primarily due to higher gasoline prices. The food index and the all items less food and energy index were up 1.0 percent and 1.6 percent, respectively, over the year. (See table 1.)

Food

Food prices were unchanged in May. The food at home index (groceries) fell 0.9 percent, while the food away from home (restaurant, cafeteria, and vending purchases) index increased 1.2 percent. Within the food at home group, indexes were higher in May for citrus fruits, lettuce, and pork chops. Prices were lower for frozen fruits and vegetables and tomatoes.

From May 2017 to May 2018, the food index increased 1.0 percent. Over the year, costs for food away from home rose 3.1 percent. Grocery prices were 0.7 percent lower.

Energy

The energy index increased 4.9 percent in May, primarily due to a 7.9-percent rise in gasoline prices. Utility (piped) gas service costs rose 1.9 percent, and electricity costs increased 0.6 percent in May.

Over the year, the Chicago area energy index rose 13.2 percent. From May 2017 to May 2018, gasoline prices rose 25.3 percent, and the electricity index was 3.8 percent higher. The index for utility (piped) gas service fell 4.1 percent.

All items less food and energy

The index for all items less food and energy edged up 0.1 percent in May. Among the index’s components, prices were higher for shelter (0.6 percent) and medical care (1.0 percent) but lower for apparel (-6.6 percent).

Over the year, the index for all items less food and energy rose 1.6 percent. A 3.6-percent increase in the index for owners’ equivalent rent of primary residence was the major contributing factor.

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

Month	2014		2015		2016		2017		2018
	1-month	12-month	1-month	12-month	1-month	12-month	1-month	12-month	1-month	12-month
January	0.9	1.2	-0.2	0.4	0.8	0.9	0.7	1.8	0.8	1.8
February	0.5	0.7	0.0	-0.2	-0.2	0.7	0.1	2.2	0.0	1.6
March	1.1	1.9	0.7	-0.6	0.1	0.2	-0.1	2.0	0.0	1.8
April	0.5	2.4	0.1	-0.9	0.6	0.7	0.4	1.7	0.7	2.1
May	-0.1	1.8	0.3	-0.5	0.0	0.3	0.2	1.8	0.4	2.3
June	0.4	2.0	0.2	-0.7	0.5	0.7	0.0	1.3
July	-0.4	1.9	-0.1	-0.5	-0.8	-0.1	0.0	2.2
August	0.1	1.9	0.4	-0.1	0.2	-0.2	0.3	2.3
September	0.0	2.1	-0.3	-0.4	0.6	0.6	0.4	2.1
October	-0.4	2.0	-0.1	-0.2	0.1	0.8	-0.4	1.6
November	-0.8	1.6	-0.4	0.2	0.2	1.5	0.4	1.8
December	-0.4	1.5	-0.6	0.0	-0.2	1.9	-0.4	1.7

The June 2018 Consumer Price Index for Chicago is scheduled to be released on Thursday, July 12, 2018.

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 93 percent of the total population and (2) a CPI for Urban Wage Earners and Clerical Workers (CPI-W) which covers approximately 29 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 75 urban areas across the country from about 5,000 housing units and approximately 22,000 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-Naperville-Elgin, Ill.-Ind.-Wis., Core Based Statistical Area covered in this release is comprised of Cook, DeKalb, DuPage, Grundy, Kane, Kendall, Lake, McHenry, and Will Counties in Illinois; Jasper, Lake, Newton, and Porter Counties in Indiana; and Kenosha County in Wisconsin.

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