Year	Percent
1991	79.259
1992	78.61
1993	75.943
1994	75.513
1995	77.719
1996	78.485
1997	77.832
1998	79.961
1999	80.951
2000	81.947
2001	82.324
2002	79.395
2003	78.52
2004	77.156
2005	78.586
2006	79.595
2007	80.062
2008	78.557
2009	72.213
2010	72.57
2011	72.299
2012	72.935
2013	74.252
2014	76.372
2015	77.779
2016	79.909
2017	79.525
2018	78.928
2019	78.299
2020	77.644
2021	76.983
2022	76.317