Year	Percent
1991	69.381
1992	66.771
1993	63.997
1994	63.323
1995	63.444
1996	62.867
1997	63.809
1998	65.403
1999	67.314
2000	66.819
2001	67.468
2002	68.043
2003	68.15
2004	68.006
2005	73.751
2006	73.467
2007	73.702
2008	72.472
2009	73.205
2010	72.139
2011	71.332
2012	71.538
2013	71.389
2014	70.123
2015	67.099
2016	67.008
2017	66.992
2018	66.964
2019	66.909
2020	66.854
2021	66.798
2022	66.743