Year	per 1,000 people
1990	3.93
1991	3.797
1992	3.89
1993	3.797
1994	3.637
1995	3.659
1996	3.589
1997	3.287
1998	3.437
1999	3.314
2000	3.213
2001	3.356
2002	3.498
2003	3.543
2004	3.528
2005	3.546
2006	3.635
2007	3.585
2008	3.639
2009	3.698
2010	3.839
2011	3.861
2012	3.831
2013	3.878
2014	3.914
2015	3.909
2016	4.127
2017	3.939
2018	3.931
2019	3.948
2020	4.028