Year	per 1,000 people
1960	3.18740749359131
1970	2.84249997138977
1986	2.48839998245239
1988	2.62899994850159
1989	2.56439995765686
1990	2.4993000031
1994	2.1031999588
1998	2.0999999046
2004	1.7
2015	1.9