Year	per 1,000
1990	3.073650938183484
1991	3.063453781181976
1992	2.9698631779475795
1993	2.9049823255112424
1994	2.796402303884555
1995	2.6912290582376714
1996	2.6525621323522675
1997	2.6285835335986554
1998	2.5605399957919146
1999	2.5056378700098323
2000	2.432348389035345
2001	2.354995867382887
2002	2.2284348763531616
2003	2.15600344452647
2004	2.094452028061791
2005	2.0287743952760646
2006	1.9585578641504566
2007	1.8930856335237305
2008	1.8086157430024037
2009	1.7359348276531517
2010	1.622742012580828
2011	1.5413837523594516
2012	1.463333587379653
2013	1.3836212821673974
2014	1.323549709677112
2015	1.3012301113018168
2016	1.2867417280467008
2017	1.2396414184172113
2018	1.213204259618848
2019	1.1976123768714457
2020	1.2001811642322726
2021	1.2026543249026684
2022	1.2230254429632803