Year	per 1,000
1990	2.4
1991	2.5
1992	3.4
1993	4.6
1994	4.9
1995	4.2
1996	3.4
1997	3
1998	2.6
1999	2.3
2000	2
2001	1.8
2002	1.7
2003	1.8
2004	1.8
2005	1.9
2006	2
2007	2.1
2008	2.1
2009	2.3
2010	2.4
2011	2.3
2012	2.1
2013	2.1
2014	2.3
2015	2.8
2016	3.1
2017	3
2018	2.6
2019	2.3
2020	2.3
2021	2.9
2022	4.6