Year	Percent
1991	59.588
1992	61.33
1993	61.967
1994	63.111
1995	63.665
1996	64.863
1997	65.964
1998	66.319
1999	66.147
2000	66.101
2001	65.838
2002	65.499
2003	64.859
2004	64.523
2005	63.902
2006	63.848
2007	63.688
2008	63.033
2009	63.399
2010	63.565
2011	63.546
2012	63.54
2013	63.429
2014	63.568
2015	63.797
2016	64.206
2017	64.06
2018	63.908
2019	63.757
2020	63.596
2021	63.441
2022	63.28