Year	per 1,000
1990	9.060934043299088
1991	8.841203674289478
1992	8.671641244181398
1993	8.536037095350675
1994	8.454962787889048
1995	8.386102498328876
1996	8.299680648856409
1997	8.229940767623876
1998	8.216067613335465
1999	8.136485509358753
2000	8.091247622652443
2001	8.103980919842199
2002	8.073111085179502
2003	7.949680158287756
2004	7.798957204915055
2005	7.625412765190482
2006	7.554676858351442
2007	7.567206428431387
2008	7.61256591334177
2009	7.64215523273564
2010	8.248577268717044
2011	7.573869327784386
2012	7.4628362782844295
2013	7.343097487502756
2014	7.31561596549383
2015	7.285594390449629
2016	7.287760737736026
2017	7.277162851549134
2018	7.227446311337005
2019	7.1328896563968645
2020	7.112916476440443
2021	7.125507299237068
2022	7.14521942689793