Year	per 1,000
1990	22.37860518180102
1991	21.87325450483104
1992	21.11306709063923
1993	21.098596336068322
1994	27.942263582486856
1995	20.02517393171867
1996	19.926115973898455
1997	19.2147135422146
1998	18.81711944138316
1999	18.84805408712104
2000	17.790237862051285
2001	17.166695491281665
2002	16.58351185963826
2003	15.903830753115377
2004	15.338813388855892
2005	14.76904697884636
2006	14.303003198550671
2007	13.922584484595996
2008	14.092895700903755
2009	13.317106316617172
2010	13.487340630392335
2011	12.84956864621356
2012	12.610767613107205
2013	12.359192876527283
2014	12.12024587200322
2015	12.081947753429661
2016	11.804492425593471
2017	11.656605886887466
2018	11.712808891175944
2019	11.577004069209215
2020	11.49011477666592
2021	11.494147252916278
2022	11.426490594725594