Veterans: Period of Service.
Veterans: Civilians who have served (even for a short time), but are not currently serving, on active duty in the U.S. Army, Navy, Air Force, Marine Corps, or the Coast Guard, or who served in the U.S. Merchant Marine during World War II. People who served in the National Guard or Reserves are classified as veterans only if they were ever called or ordered to active duty. People who indicate that they had ever served on active duty, were currently on active duty, were asked to indicate the period or periods in which they served. Currently, there are 9 periods of service on the ACS questionnaire. Respondents are instructed to mark a box for each period in which they served, even if just for part of the period. The periods were determined by the Department of Veterans Affairs (VA) and generally alternate between peacetime and wartime.
Source: U.S. Census Bureau; 2013-2017 American Community Survey 5-Year Estimates, Table B21002.