Year	Percent
1991	37.755
1992	38.922
1993	39.106
1994	39.807
1995	40.698
1996	41.165
1997	39.121
1998	38.837
1999	41.35
2000	42.745
2001	46.587
2002	42.135
2003	39.504
2004	42.216
2005	44.999
2006	47.603
2007	49.241
2008	50.469
2009	48.713
2010	45.085
2011	46.586
2012	46.687
2013	44.852
2014	44.828
2015	44.172
2016	46.854
2017	47.205
2018	47.699
2019	48.212
2020	48.448
2021	48.572
2022	48.664