Year	per 1,000 people
1985	3.72
1986	3.816
1987	3.885
1988	3.941
1989	3.977
1990	3.908
1991	3.813
1992	3.493
1993	3.507
1994	3.582
1995	3.568
1996	3.597
1997	3.637
1998	3.604
1999	3.603
2000	3.526
2001	3.54
2002	3.626
2003	3.611
2004	3.578
2005	3.664
2006	3.731
2007	3.835
2008	3.85
2009	3.833
2010	3.895
2011	4.003
2012	4.115
2013	4.177
2014	4.218
2015	4.253
2016	4.367
2017	4.437
2018	4.479
2019	4.481
2020	4.442
2021	4.95