Year	Percent
1991	68.395
1992	68.296
1993	68.16
1994	68.026
1995	67.923
1996	68.026
1997	68.112
1998	68.172
1999	68.181
2000	68.123
2001	68.711
2002	69.137
2003	69.478
2004	70.597
2005	71.733
2006	72.563
2007	73.341
2008	74.069
2009	74.748
2010	75.388
2011	77.119
2012	78.892
2013	78.1
2014	77.31
2015	76.105
2016	75.415
2017	75.826
2018	76.24
2019	76.641
2020	76.955
2021	77.261
2022	77.557