consumer price index

 An index of the cost of all goods and services to a typical consumer, calculated and published by the United States Bureau of Labor Statistics; abbreviated CPI, and usually referred to by that acronym. The Bureau maintains several indices for different groups of consumers, but the most commonly referred to is the index for “All urban consumers”, called the CPI-U. The increase of this value each year is one measure of monetary inflation.  [WordNet 1.5]