Year	per 1,000
1990	1.2619447347398822
1991	1.210572751263712
1992	1.1707733370450388
1993	1.14452005257736
1994	1.1451795557724729
1995	1.1516396089123162
1996	1.1240273213839815
1997	1.0747149644776635
1998	0.9868437831031319
1999	0.9138288809671082
2000	0.8352784841111601
2001	0.7780798396089692
2002	0.7515189013145454
2003	0.6976951773851958
2004	0.6572028407296374
2005	0.6461629548207863
2006	0.6348920476354305
2007	0.6055505817645057
2008	0.5843429231520836
2009	0.5332844744665187
2010	0.5109486828059348
2011	0.4890321865713715
2012	0.48290546857125494
2013	0.4631027002278351
2014	0.4537236062800072
2015	0.44893409752514074
2016	0.44326498975896433
2017	0.4182436685332967
2018	0.40149789496680655
2019	0.3999123882140752
2020	0.3982131710726007
2021	0.38524663929052716
2022	0.3838437011536828