Year	Percent
1991	67.029
1992	66.83
1993	68.218
1994	69.557
1995	70.388
1996	68.893
1997	64.341
1998	61.05
1999	59.124
2000	57.804
2001	59.474
2002	61.909
2003	64.712
2004	65.237
2005	68.066
2006	68.481
2007	70.95
2008	73.642
2009	77.1
2010	80.145
2011	75.544
2012	72.979
2013	72.735
2014	73.769
2015	75.515
2016	74.581
2017	74.035
2018	73.945
2019	74.494
2020	75.603
2021	73.084
2022	71.344