Year	per 1,000 people
1981	0.5
1982	0.5
1983	0.5
1984	0.6
1985	0.6
1986	0.6
1987	0.7
1988	0.7
1989	0.8
1990	0.811
1991	0.875
1992	0.948
1993	1.012
1994	1.057
1995	1.116
1996	1.169
1997	1.233
1998	1.269
1999	1.315
2000	1.302
2001	1.396
2002	1.499
2003	1.579
2004	1.576
2005	1.636
2006	1.7
2007	1.752
2008	1.871
2009	1.949
2010	2.014
2011	2.062
2012	2.098
2013	2.174
2014	2.209
2015	2.242
2016	2.289
2017	2.342
2018	2.385
2019	2.457
2020	2.508