Year	Percent
1991	71.816
1992	72.678
1993	73.905
1994	74.239
1995	73.471
1996	71.551
1997	71.499
1998	69.525
1999	65.87
2000	66.184
2001	70.771
2002	70.577
2003	72.08
2004	72.601
2005	74.167
2006	73.875
2007	74.887
2008	74.95
2009	74.658
2010	75.443
2011	76.37
2012	77.253
2013	77.056
2014	77.585
2015	77.693
2016	77.092
2017	76.897
2018	76.771
2019	76.656
2020	76.562
2021	76.482
2022	76.406