Year	per 1,000
1990	8.977573569322866
1991	8.858568168697698
1992	8.710041205881396
1993	8.66244235392081
1994	8.593068288116092
1995	8.539313000275358
1996	8.550802723402454
1997	8.508464044273499
1998	8.537993999723858
1999	8.521368385886685
2000	8.458324105692903
2001	8.379442741683242
2002	8.20791324646745
2003	8.06850490959631
2004	7.990585716542711
2005	7.7387311220425925
2006	7.474596249884104
2007	7.29047983776581
2008	7.149302000804268
2009	6.8802110828439815
2010	6.74542581195589
2011	6.496512523271369
2012	6.31366724993167
2013	6.169723559112645
2014	6.0414742364214655
2015	5.929625865562761
2016	5.817100074301628
2017	5.714415488058439
2018	5.627898762027075
2019	5.540481910098362
2020	5.475747440750266
2021	5.438848829931866
2022	5.4451503469820395