Year	per 1,000
1990	8.5
1991	9.2
1992	10.3
1993	11.6
1994	12.5
1995	14.7
1996	12.6
1997	12.8
1998	13.3
1999	13.8
2000	14
2001	13.9
2002	13.4
2003	12.6
2004	11.9
2005	11.5
2006	11
2007	10.3
2008	9.5
2009	8.8
2010	8.3
2011	7.9
2012	7.5
2013	7.2
2014	6.7
2015	6.2
2016	5.7
2017	5.2
2018	4.9
2019	4.8
2020	4.7
2021	4.8
2022	7.2