Year	per 1,000 people
1977	7.6
1978	6.3
1979	7.9
1980	7.6
1981	7.5
1982	7.9
1983	8.3
1984	8.3
1985	8.2
1986	8.3
1987	8.2
1988	7.9
1989	8.2
1990	8.4
1991	8.3
1992	8
1993	7.8
1994	8
1995	8.6
1996	7.9
1997	8.8
1998	8.1
1999	8.5
2000	8
2001	8.3
2002	7.9
2003	7.2
2004	8.4
2005	8.2
2006	7.8
2007	8
2008	7.6
2009	7.8
2010	9
2011	8.4
2012	8
2013	7.9
2014	8.2
2015	8.4
2016	8.7
2017	8.9
2018	8.7
2019	9.8
2020	9.2
2021	9.4
2022	9.3