Year	Percent
1991	51.93
1992	51.977
1993	51.366
1994	50.71
1995	49.619
1996	48.736
1997	46.867
1998	48.403
1999	49.946
2000	54.763
2001	59.579
2002	64.759
2003	69.735
2004	74.413
2005	74.361
2006	74.239
2007	74.155
2008	74.158
2009	73.761
2010	73.594
2011	73.5
2012	73.531
2013	73.745
2014	73.826
2015	73.783
2016	73.603
2017	73.824
2018	74.02
2019	74.234
2020	74.442
2021	74.648
2022	74.854