Civilian Labor Force is the term used by term used by the Bureau of Labor Statistics (BLS) in the US for describing all the people who form the labor force of the country. It includes all the Americans who are either employed, seeking employment, at least 16 years of age, not serving in the US Military and are not institutionalized. It basically includes all the Americans who are eligible to work in the US.
Currently the civilian labor force in the US is in the range of 140-150 million people. It accounts for roughly around half of the total population on America.
The graph above shows the trend in civilian labor force in the US as a percentage of total population. There has been a sharp increase in the labor force from the 1960s because of inclusion of women in the work force. In the 1990s the internet boom increased the labor force and later the dot com crash caused the rate to fall. This was again restored in the mid 2000s due to the housing boom and has yet again declined after the hosing crash of 2008.