Year	per 1000 people
1960	1.4
1961	1.4
1962	1.4
1963	1.4
1964	1.4
1965	1.4
1966	1.4
1967	1.4
1968	1.4
1969	1.5
1970	1.5
1971	1.6
1972	1.6
1973	1.7
1974	1.8
1975	1.9
1976	2
1977	2.1
1978	2.2
1979	2.4
1980	2.5
1981	2.6
1982	2.6
1983	2.6
1984	2.6
1985	2.7
1986	2.8
1987	2.9
1988	3
1989	2.9
1990	3
1991	3
1992	3
1993	3.1
1994	3.1
1995	3.2
1996	3.2
1997	3.3
1998	3.3
1999	3.4
2000	3.5
2001	3.5
2002	3.615
2006	3.97
2010	3.806
2011	3.826
2012	3.903
2013	4.025
2014	4.114
2015	4.189
2016	4.248