Year	Percent
1991	41.141
1992	40.55
1993	40.129
1994	41.619
1995	43.101
1996	46.079
1997	48.108
1998	49.912
1999	49.232
2000	52.168
2001	52.621
2002	53.055
2003	53.363
2004	53.684
2005	53.961
2006	53.025
2007	52.064
2008	51.927
2009	47.344
2010	42.729
2011	45.55
2012	47.034
2013	46.73
2014	46.338
2015	45.965
2016	45.574
2017	45.368
2018	45.181
2019	45.01
2020	44.847
2021	44.691
2022	44.543