Year	Percent
1991	78.79
1992	78.82
1993	79.224
1994	79.123
1995	79.023
1996	76.25
1997	77.75
1998	78.874
1999	77.513
2000	76.991
2001	77.033
2002	76.148
2003	76.885
2004	75.468
2005	76.415
2006	76.47
2007	77.811
2008	76.067
2009	72.689
2010	71.153
2011	71.231
2012	70.398
2013	70.853
2014	70.909
2015	69.934
2016	68.46
2017	68.887
2018	68.906
2019	68.876
2020	68.772
2021	68.621
2022	68.415