The Indonesian National Armed Forces are the military forces of the Republic of Indonesia. It consists of the Army (TNI-AD), Navy (TNI-AL), and Air Force (TNI-AU). The President of Indonesia is the commander-in-chief of the Armed Forces. In 2016, it comprises approximately 395,500 military personnel including the Indonesian Marine Corps (Korps Marinir), which is the branch of the Navy. The Indonesian Armed Forces was formed during the Indonesian National Revolution, when it undertook a guerrilla war along with informal militia. As a result of this, and the need to maintain internal security, the Armed forces including the Army, Navy, and Air Force has been organised along territorial lines, aimed at defeating internal enemies of the state and potential external invaders. The Indonesian armed forces are voluntary. The active military strength is 395,500 with available manpower fit for military service of males aged between 16 and 49 is 75,000,000, with a further 4,500,000 new suitable for service annually. Military spending in the national budget was widely estimated 3% of GDP in 2005, but is supplemented by revenue from many military-run businesses and foundations. The defence budget for 2017 was $8.17bn. The Indonesian armed forces (Military) personnel does not include members of law enforcement and paramilitary personnel such as the Indonesian National Police (Polri) consisting of approximately 590,000+ personnel, Mobile Brigade Corps (Brimob) of around 42,000+ armed personnel, the Civil Service Police Unit (Municipal police) or Satpol PP, Indonesian College Students' Regiment or Resimen Mahasiswa (Menwa) which is a collegiate military service consisting 26,000 trained personnel, and civil defence personnel (Linmas or Public Protection Service Corps, which replaced the old Hansip in 2014).