In the United States, the labor force (or workforce) is defined as individuals age 16 or older who either have jobs or can work and are looking for jobs. People under 16 are not considered part of the workforce, even though many young people in the United States work. Another way of defining the labor force is the sum of people employed plus the number of unemployed. This does not, however, distinguish between part-time and full-time EMPLOYMENT. During RECESSIONs people can often only find part-time work, causing labor-force statistics to underestimate the true level of UNEMPLOYMENT. To be part of the labor force, one has to be employed or looking and available for a job. Some people choose to leave the labor force, usually after their unemployment benefits have ended but sometimes for health or personal reasons. Others, discouraged because they cannot find the employment they want, simply drop out of the workforce. The definition of labor force may vary among countries. In the United States, the DEPARTMENT OF LABOR’s BUREAU OF LABOR STATISTICS (BLS) surveys and estimates labor-force and related statistics. The labor-force statistic is used to calculate the country’s unemployment rate; the number of people unemployed divided by the labor-force number, is the nation’s unemployment rate expressed as a percentage. The BLS also calculates labor-force participation rates, the percentage of working-age individuals who are working or seeking work, by category. One of the trends in the American labor market has been the increase in the participation of women in the workforce, rising from less than 40 percent in 1950 to over 60 percent in 2000. During the same period, the labor-force participation rate among males actually declined slightly, from over 80 percent to approximately 75 percent. As would be expected, the participation rate is low among people under 20 years old and over 55 years old, and slightly lower among minority groups in the United States.