Year	per 1,000
1990	6.023487375028262
1991	5.778696475250273
1992	5.4024705768786
1993	5.103432589138602
1994	4.822776653405218
1995	4.55132583114202
1996	4.303829332543046
1997	4.096951253841997
1998	3.9110665368867545
1999	3.7208988198486743
2000	3.608749196839879
2001	3.4235250651473716
2002	3.300427490707786
2003	3.165202718955928
2004	3.65550055890745
2005	2.8763577518428054
2006	2.7348659519001153
2007	2.5903943529223175
2008	3.41202576848707
2009	2.3172709022861464
2010	2.1942958136116255
2011	2.121891942507181
2012	1.9950516019296454
2013	1.9824638095173763
2014	1.822719004373431
2015	1.7660948580356461
2016	1.660324690470321
2017	1.6179033911661311
2018	1.5744486978765813
2019	1.4832587056977065
2020	1.45255909961685
2021	1.4241226810108247
2022	1.3366953982061394