Year	per 1,000
1990	3.5407147095753535
1991	3.58311137752411
1992	3.476301371134753
1993	3.4159444578893714
1994	3.2926166238295598
1995	3.1871098699191345
1996	3.1244430818911204
1997	3.0934127475653717
1998	2.9912120959597575
1999	2.879974569909769
2000	2.765128290340269
2001	2.6907234528805914
2002	2.6075485395286333
2003	2.5631376319659243
2004	2.5639469161454156
2005	2.5840620720476792
2006	2.5948463993769386
2007	2.589867849566722
2008	2.5370427008024548
2009	2.4728501648899943
2010	2.3055633398127635
2011	2.2154707643987313
2012	2.1025612772818554
2013	2.014386116351934
2014	1.9582755824226994
2015	1.906246041956259
2016	1.8905893585602735
2017	1.831077720235867
2018	1.8267556969446503
2019	1.8123038382598817
2020	1.8289577407070576
2021	1.8058698723138298
2022	1.7741037676309572