Year	per 1,000
1990	9.252016246308095
1991	8.98448202575859
1992	8.778245613980085
1993	8.610533409331236
1994	8.514819066769821
1995	8.441232785653943
1996	8.363021400306533
1997	8.300095470693092
1998	8.272946752774752
1999	8.1589299760958
2000	8.056516586939146
2001	8.00613214977855
2002	7.917018496795813
2003	7.7509037175246425
2004	7.57926839378134
2005	7.3867714160407125
2006	7.2856605245759605
2007	7.267782496364946
2008	7.293571323664099
2009	7.314312951968076
2010	7.963779979618992
2011	7.233995206805669
2012	7.1130440468286285
2013	6.974651258816604
2014	6.928739396916392
2015	6.89370395043691
2016	6.9025791551847115
2017	6.9007710975857135
2018	6.887460471177208
2019	6.835164787260578
2020	6.824474560917292
2021	6.839429218396379
2022	6.842454822908163