As of 2002, the total armed forces of Portugal numbered 43,600 active personnel including 2,875 women. Reservists numbered 210,930 for all services. The army had 25,400 personnel with equipment including 187 main battle tanks. The navy of 10,800, including 1,580 marines, had two submarines, six frigates, and 28 patrol and coastal combatants. The air force of 7,400 was equipped with 50 combat aircraft. Paramilitary police and republican guards number 40,900. The US maintains a military presence with 770 troops. Portugal has air force personnel in São Tome, and participates in peacekeeping operations in six regions. Defense spending in 1999–00 was $1.3 billion, representing2.2% of GDP.