Year	per 1000 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	0.8
1991	0.9
1992	1
1993	1
1994	1.1
1995	1.1
1996	1.2
1997	1.2
1998	1.3
1999	1.3
2000	1.3
2001	1.4
2002	1.5
2003	1.573
2004	1.733
2005	1.793
2006	1.842
2007	1.898
2008	1.96
2009	2.017
2010	2.002
2011	2.054
2012	2.099
2013	2.185
2014	2.231
2015	2.273
2016	2.326