As of 2010, the military of Madagascar is composed of the 8,100 paramilitary of the National Gendarmerie and the 13,500 members of the People's Armed Forces. According to the International Institute of Strategic Studies' Military Balance 2010, the latter includes an Army of 12,500, a Navy of 500 and a 500-strong Air Force, while the CIA Factbook describes the People's Armed Forces as consisting of the Intervention Force, Aeronaval Force (navy and air) and the Development Force. Military service is voluntary and limited to males aged 18 to 25; every citizen of either gender is required to have perform either military or civil service for a minimum of 18 months. However, because of a lack of up-to-date census data, this requirement is not currently enforced. The Gendarmerie recruits Malagasy citizens between the ages of 20 and 30 (or 35 if the recruit has prior military service). Military expenses constituted just over one percent of GDP. Under Ravalomanana, military expenditure doubled from 54 million USD in 2006 to 103 million USD in 2008.