More than offsetting a decline in gasoline, the index for shelter rose in May, up 0.4 percent for the fourth consecutive month. The index for food increased 0.1 percent in May. The food away from home index rose 0.4 percent over the month, while the food at home index was unchanged. The energy index fell 2.0 percent over the month, led by a 3.6-percent decrease in the gasoline index.

The index for all items less food and energy rose 0.2 percent in May, after rising 0.3 percent the preceding month. Indexes which increased in May include shelter, medical care, used cars and trucks, and education. The indexes for airline fares, new vehicles, communication, recreation, and apparel were among those that decreased over the month.

The all items index rose 3.3 percent for the 12 months ending May, a smaller increase than the 3.4-percent increase for the 12 months ending April. The all items less food and energy index rose 3.4 percent over the last 12 months. The energy index increased 3.7 percent for the 12 months ending May. The food index increased 2.1 percent over the last year.

A measure of the average change in prices over time for a set group of goods and services. The Bureau of Labor Statistics publishes CPIs for two population groups:

• (1) for all urban consumers (CPI-U) which covers approximately 80 percent of the total population
• (2) for all urban wage earners and clerical workers (CPI-W) which covers 32 percent of the total population.

Among the CPI components are the costs of housing, food, transportation, and energy. While the CPI is not technically a cost of living index, it is often used to indicate changes in the cost-of-living.

For more assistance, call the Boston office of the Bureau of Labor Statistics at 617-565-2327.