Year	per 1,000
1990	6.459509500063205
1991	5.272165257697422
1992	4.980125445946784
1993	4.726745493003843
1994	4.523778088340107
1995	4.34410749384436
1996	4.1670181323898055
1997	3.9790159855809772
1998	3.839925480305011
1999	3.681029946135404
2000	3.5513720968548292
2001	3.4025278393962397
2002	3.2865852832009983
2003	3.5544775506868382
2004	3.1007728992934576
2005	3.0472929727710487
2006	3.0050710806369803
2007	2.9764673509890773
2008	2.9359726488275637
2009	2.9314569363780687
2010	2.879652006272384
2011	2.928248697441332
2012	3.3886073796799594
2013	3.4005547475521096
2014	3.2503297695265547
2015	3.1629238333934273
2016	2.8226460784662217
2017	2.792115034093612
2018	2.786042421280614
2019	2.42212639490862
2020	2.217815586511238
2021	2.2004435950615022
2022	2.0443939324324854