Year	per 1,000 people
1960	1
1961	1
1962	1.1
1963	1.1
1964	1.2
1965	1.2
1966	1.3
1967	1.3
1968	1.4
1969	1.4
1970	1.4
1971	1.5
1972	1.5
1973	1.5
1974	1.6
1975	1.6
1976	1.6
1977	1.7
1978	1.7
1979	1.7
1980	1.8
1981	1.8
1982	1.8
1983	1.9
1984	1.9
1985	2
1986	2
1987	2.1
1990	2.145
1991	2.173
1992	2.189
1993	2.228
1994	2.286
1995	2.329
1996	2.365
1997	2.373
1998	2.347
1999	2.282
2000	2.208
2001	2.243
2002	2.279
2003	2.408
2004	2.266
2005	2.115
2006	2.156
2007	2.168
2008	2.139
2009	2.148
2010	2.156
2011	2.181
2012	2.201
2013	2.208
2014	2.273
2015	2.294
2016	2.381
2017	2.343
2020	3.714