Total armed strength in 2002 was 82,300, including 23,000 members of the Fuerzas Armados de Cooperacion , an internal security force. The army had 34,000 regulars, including six infantry divisions and 12 specialized brigades. Equipment included 81 main battle tanks and close to 200 light tanks. The navy had 18,300 members, including 7,800 marines, 1,000 Coast Guard members, and 500 Naval Aviators; naval strength included two submarines and six frigates. The air force had 7,000 personnel, 125 combat aircraft, and 31 armed helicopters. Defense expenditures in 1999 were $934 million, or 0.9% of the GDP.