Historically, the use of children for military purposes has been widespread—see Children in the military—but has been in decline in the 21st century. According to Child Soldiers International, as of 2017 approximately two-thirds of states worldwide had committed to restrict military recruitment to adults from age 18, and at least 60 non-state armed groups had signed agreements to stop or reduce the use of children for military purposes. The organization reported that the so-called "Straight 18" standard – the restriction of all military employment to adults – had been emerging as a global norm since 2001.