Year	Percent
1991	63.953
1992	66.119
1993	65.557
1994	65.514
1995	66.147
1996	66.061
1997	66.811
1998	66.601
1999	66.609
2000	66.171
2001	67.132
2002	65.764
2003	65.786
2004	66.4
2005	66.185
2006	65.949
2007	65.586
2008	65.144
2009	64.893
2010	64.708
2011	64.438
2012	62.354
2013	59.545
2014	59.012
2015	61.69
2016	61.421
2017	61.654
2018	60.969
2019	60.352
2020	59.54
2021	58.678
2022	57.803