Year	per 1,000
1990	25.865454539247096
1991	26.89073121713268
1992	24.39627326435223
1993	23.833650210532173
1994	24.424119843996937
1995	21.91657064135619
1996	21.11540813033943
1997	20.196635553354923
1998	19.169260796323456
1999	18.0658660685498
2000	17.139622419236236
2001	16.35781848124241
2002	15.6034410816545
2003	14.952727494201026
2004	14.3611958827545
2005	13.738344312672137
2006	13.136997305979024
2007	12.539500859703166
2008	12.927506617143592
2009	11.346553256769518
2010	11.242269441338301
2011	10.33622867813778
2012	9.85147392177036
2013	9.44183693765866
2014	9.132255161371583
2015	8.905598831494219
2016	8.621444236924233
2017	8.39871895694146
2018	8.219028746914992
2019	8.021471911553292
2020	7.832941765065098
2021	7.6753756400995945
2022	7.459070160002121