Year	per 1,000
1990	4.729840361174523
1991	4.672862362394027
1992	4.65212348130515
1993	4.66922185377161
1994	4.689162890221379
1995	4.74710835872735
1996	4.7636429310259905
1997	4.805967224941181
1998	4.8022222222222215
1999	4.705746395676823
2000	4.680390127800486
2001	4.601217505239022
2002	4.616132911044223
2003	4.607157386319013
2004	4.599029845480844
2005	4.659465268594477
2006	4.678327425383952
2007	4.736230551113791
2008	4.776264525463835
2009	4.867854224119594
2010	4.943307101208062
2011	5.0624323745048185
2012	5.091271525867956
2013	5.112304385020428
2014	5.0749257379275825
2015	4.9744703841460725
2016	4.868261339967174
2017	4.714548787293093
2018	4.593867698013402
2019	4.722399024901431
2020	4.318592504663388
2021	4.189744301122674
2022	4.077134917783401