Year	per 1,000
1990	4.1
1991	4.3
1992	5.6
1993	7.2
1994	7.1
1995	5.5
1996	4.1
1997	3.4
1998	2.9
1999	2.5
2000	2.2
2001	2.1
2002	2
2003	2.1
2004	2.3
2005	2.4
2006	2.6
2007	2.6
2008	2.7
2009	2.8
2010	2.9
2011	2.8
2012	2.6
2013	2.5
2014	2.7
2015	3.1
2016	3.4
2017	3.1
2018	2.7
2019	2.4
2020	2.3
2021	2.7
2022	4.6