Year	Percent
1991	43.355
1992	43.286
1993	43.551
1994	43.451
1995	43.267
1996	43.475
1997	43.444
1998	43.198
1999	43.015
2000	43.138
2001	42.759
2002	42.634
2003	42.422
2004	42.334
2005	42.263
2006	42.221
2007	42.181
2008	41.449
2009	41.941
2010	41.939
2011	43.531
2012	44.883
2013	47.315
2014	48.335
2015	48.604
2016	48.593
2017	48.797
2018	49.015
2019	49.192
2020	49.362
2021	49.507
2022	49.624