Year	Percent
1991	76.055
1992	76.87
1993	76.326
1994	76.876
1995	76.629
1996	74.986
1997	75.908
1998	75.224
1999	75.785
2000	74.093
2001	72.261
2002	70.813
2003	67.629
2004	65.41
2005	63.649
2006	65.102
2007	66.991
2008	68.829
2009	70.275
2010	68.422
2011	66.913
2012	65.968
2013	67.175
2014	67.319
2015	70.096
2016	68.803
2017	68.672
2018	68.461
2019	68.224
2020	68.002
2021	67.787
2022	67.58