Year	per 1,000
1990	20.644784209911233
1991	19.51514961673174
1992	19.374931964311568
1993	19.4535608041965
1994	18.934939240847598
1995	18.640362534312924
1996	18.63149980085893
1997	17.84934864242494
1998	17.558465483109803
1999	17.75720471390506
2000	16.893103912833233
2001	16.548593191398908
2002	16.212998054949953
2003	15.81787300480647
2004	15.444368545705515
2005	15.060012618823315
2006	14.756637291515723
2007	14.438286905561016
2008	14.668652624169892
2009	13.794914253848674
2010	14.00380186710701
2011	13.4643320713824
2012	13.894890964496776
2013	13.713342378616998
2014	13.462178379853315
2015	13.505092018341998
2016	13.167134972807087
2017	13.055934318017398
2018	13.015635737885054
2019	12.57891178672798
2020	12.266680493893965
2021	12.137399285929718
2022	12.299383009287663