Year	per 1000 people
1960	0.8
1961	0.8
1962	0.9
1963	0.8
1964	0.8
1965	0.9
1966	0.9
1967	0.9
1968	1
1969	0.9
1970	0.9
1971	1
1972	1
1973	1.1
1974	1.2
1975	1.2
1976	1.3
1977	1.5
1978	1.7
1979	1.9
1980	2
1981	2.1
1982	2.2
1983	2.3
1984	2.4
1985	2.5
1986	2.6
1987	2.6
1988	2.7
1989	2.8
1990	2.8
1991	2.8
1992	2.9
1993	2.9
1994	2.9
1995	2.9
1996	3
1997	3
1998	3.1
1999	3.1
2000	3.2
2001	3.2
2002	3.257
2003	3.311
2004	3.372
2005	3.448
2006	3.511
2007	3.593
2008	3.681
2009	3.786
2010	3.842
2011	3.983
2012	4.101
2013	4.26
2014	4.426