Year	per 1,000 people
1960	1
1961	1
1962	1
1963	1
1964	1
1965	1
1966	1
1967	1
1968	1.1
1969	1.1
1970	1.1
1971	1.2
1972	1.2
1973	1.2
1974	1.2
1975	1.3
1976	1.3
1977	1.3
1978	1.5
1979	1.6
1980	1.7
1981	1.5
1982	1.7
1983	1.7
1984	1.7
1985	1.8
1986	1.9
1987	1.8
1988	1.9
1989	2
1990	2.009
1991	2.019
1992	2.079
1993	2.138
1994	2.164
1995	2.242
1996	2.319
1997	2.4
1998	2.4354
1999	2.4878
2000	2.1509
2001	2.2172
2002	2.2696
2003	2.4011
2004	2.4568
2005	2.56
2006	2.578
2007	2.694
2008	2.718
2009	2.709
2010	2.773
2011	2.767
2012	2.806
2013	2.83
2014	2.881
2015	2.908
2016	2.885
2017	2.985