The US Coast Guard Academy (USCGA) is the smallest of the nation's five service academies, with an annual enrollment of fewer than 1,000 cadets. Each year's freshman class, known as "swabs," is selected through a nationwide competition. Unlike the other service academies, admission is solely merit-based and congressional nominations are not required. Graduates are commissioned as ensigns in the US Coast Guard and must serve for five years (about 85% choose to serve beyond the five-year commitment). The academy began with the School of Instruction for the Revenue Marine in 1876.