Year	Percent
1991	63.537
1992	65.589
1993	65.409
1994	65.535
1995	65.719
1996	65.504
1997	65.649
1998	65.949
1999	66.306
2000	66.653
2001	66.577
2002	66.778
2003	66.904
2004	66.612
2005	66.289
2006	65.925
2007	65.588
2008	65.164
2009	64.69
2010	64.148
2011	63.557
2012	62.917
2013	62.246
2014	60.396
2015	60.344
2016	60.44
2017	60.372
2018	60.323
2019	60.286
2020	60.26
2021	60.237
2022	60.298