Year	Percent
1991	48.68
1992	48.142
1993	45.315
1994	43.752
1995	43.984
1996	44.434
1997	44.487
1998	43.873
1999	44.128
2000	43.513
2001	43.605
2002	44.402
2003	45.204
2004	48.667
2005	51.04
2006	50.197
2007	49.731
2008	49.94
2009	48.052
2010	47.831
2011	52.515
2012	50.254
2013	47.729
2014	46.162
2015	44.494
2016	42.553
2017	42.192
2018	41.773
2019	41.795
2020	42.071
2021	42.532
2022	42.481