Year	Percent
1991	76.188
1992	76.165
1993	76.091
1994	76.047
1995	75.915
1996	76.037
1997	76.06
1998	75.953
1999	75.878
2000	76.25
2001	76.506
2002	74.52
2003	74.32
2004	74.555
2005	76.629
2006	78.609
2007	76.21
2008	74.113
2009	71.96
2010	69.825
2011	68.097
2012	75.796
2013	65.883
2014	68.867
2015	70.709
2016	69.649
2017	69.518
2018	69.335
2019	69.145
2020	68.998
2021	68.88
2022	68.787