Year	per 1,000
1990	1.6
1991	1.6
1992	1.7
1993	1.7
1994	1.7
1995	1.8
1996	1.8
1997	1.8
1998	1.8
1999	1.8
2000	1.8
2001	1.8
2002	1.8
2003	1.8
2004	1.7
2005	1.7
2006	1.7
2007	1.6
2008	1.6
2009	1.6
2010	1.6
2011	1.5
2012	1.5
2013	1.5
2014	1.4
2015	1.4
2016	1.4
2017	1.4
2018	1.3
2019	4.8
2020	1.3
2021	1.3
2022	1.2