In 2002 active armed forces numbered 177,600 including 5,520 women and were supported by some 291,000 reserves. There were 114,000 in the army, 19,000 in the navy, and 33,000 in the air force. The Greek field army has a large and varied combined arms structure, but units are manned at three different levels of readiness. The 1,250 troops serving on Cyprus include 1 mechanized brigade. The navy had 8 submarines, 2 destroyers, 12 frigates, and 40 patrol and coastal combatantss as well as 18 armed helicopters. The air force had 418 combat aircraft. The paramilitary consisted of 4,000 coast guards and customs officers. Greek military personnel provided support to UN and peacekeeping missions in seven regions around the world. Defense expenditures in 1999–00 were $6.1 billion or 4.9% of GDP. The United States has one major naval base on Greek soil and several smaller installations.