Year	Percent
1991	69.55
1992	67.388
1993	70.962
1994	70.911
1995	69.665
1996	70.381
1997	69.441
1998	69.905
1999	69.738
2000	71.336
2001	73.34
2002	75.256
2003	78.735
2004	80.149
2005	80.219
2006	80.689
2007	80.574
2008	80.817
2009	78.024
2010	75.382
2011	71.808
2012	71.101
2013	70.901
2014	71.649
2015	71.582
2016	71.771
2017	72.886
2018	73.09
2019	73.127
2020	73.212
2021	73.185
2022	73.157