Year	Percent
1991	64.533
1992	65.842
1993	66.403
1994	65.893
1995	66.042
1996	64.377
1997	63.592
1998	63.554
1999	62.938
2000	62.57
2001	62.119
2002	61.731
2003	61.22
2004	61.392
2005	61.234
2006	60.898
2007	59.816
2008	60.834
2009	62.907
2010	63.882
2011	64.36
2012	64.715
2013	65.22
2014	65.614
2015	65.874
2016	66.832
2017	66.229
2018	65.95
2019	65.643
2020	65.289
2021	64.861
2022	64.414