Official national poverty data are calculated using the Census Bureau definition of poverty. This measure has remained mostly unchanged since it was introduced in the 1960s, other than to be annually adjusted for inflation using the Consumer Price Index, and is useful for measuring long-term poverty trends. The Census Bureau releases the poverty data in an annual report, the most recent of which was released in September 2013 as Income, Poverty, and Health Insurance Coverage in the United States: 2012.

The Census definition, or rate, determines poverty by comparing pretax cash income against a poverty threshold dollar amount that is adjusted for family size and composition. In 2012, according to the official measure, 46.5 million people, or 15 percent of the total U.S. population, lived in poverty.

Read more from the Institute for Research on Poverty

View the Census Bureau table of the percent of people below the poverty level in the past 12 months by state: Act Now