Year	per 1,000
1990	4.833573896409654
1991	4.833108565897018
1992	4.755503119258985
1993	4.764782084355067
1994	4.785004801661728
1995	4.80963411635646
1996	4.825895395088927
1997	4.753509157935714
1998	4.758615304290866
1999	4.683408398827053
2000	4.67281066410486
2001	4.660653634668536
2002	4.557568429640351
2003	4.4586367566432905
2004	4.657349600372212
2005	4.294703485646022
2006	4.166947389390007
2007	4.104897149658638
2008	4.132287108533868
2009	3.91054175199896
2010	3.7920995747555724
2011	3.7603081009068973
2012	3.6834736590289583
2013	3.6810859936646185
2014	3.693838171114317
2015	3.6534791772265365
2016	3.6799320128698114
2017	3.688024175408428
2018	3.6833179053868808
2019	3.6170765712046724
2020	3.6062787802007295
2021	3.613374018261332
2022	3.6078504629506454