Year	Percent
1991	42.859
1992	43.388
1993	44.621
1994	45.011
1995	43.949
1996	43.515
1997	59.974
1998	58.583
1999	59.242
2000	58.751
2001	58.945
2002	58.971
2003	58.481
2004	58.629
2005	58.552
2006	57.867
2007	57.45
2008	53.202
2009	53.378
2010	49.738
2011	45.353
2012	44.921
2013	43.923
2014	42.995
2015	43.707
2016	44.758
2017	45.709
2018	45.603
2019	45.496
2020	45.391
2021	45.283
2022	45.176