Year	per 1,000
1990	22.2431441651498
1991	21.663128536198847
1992	21.60387568203922
1993	21.839524463567386
1994	21.326542788027375
1995	21.222413454392804
1996	21.309257399965592
1997	20.577167371435312
1998	20.30155627496369
1999	19.90760062961851
2000	19.510786769320795
2001	19.079650755881634
2002	18.645605483763696
2003	18.209278943149457
2004	17.735719906197048
2005	17.292221591529678
2006	16.886241451601283
2007	16.51723262595723
2008	16.339221219694604
2009	15.799617881923043
2010	15.4939240034323
2011	15.189373659228536
2012	14.91553701026056
2013	14.688335105510896
2014	14.440927463274509
2015	14.242782729815314
2016	14.017488262794652
2017	13.802867212940878
2018	13.553293233321607
2019	13.402651761422044
2020	13.187177813407128
2021	13.036690071000605
2022	13.018557696507031