Year	per 1,000
1990	1.8
1991	1.8
1992	1.7
1993	1.7
1994	1.7
1995	1.6
1996	1.6
1997	1.5
1998	1.4
1999	1.4
2000	1.3
2001	1.3
2002	1.2
2003	1.1
2004	1.1
2005	1
2006	1
2007	1
2008	0.9
2009	0.9
2010	0.9
2011	0.9
2012	0.9
2013	0.9
2014	0.9
2015	0.9
2016	0.9
2017	0.9
2018	0.9
2019	0.9
2020	0.9
2021	1
2022	1