Year	Percent
1991	61.778
1992	59.166
1993	61.428
1994	60.648
1995	57.878
1996	58.298
1997	58.093
1998	59.57
1999	59.278
2000	60.309
2001	63.669
2002	64.604
2003	62.867
2004	72.288
2005	69.822
2006	67.071
2007	65.653
2008	65.105
2009	66.12
2010	61.336
2011	58.805
2012	54.211
2013	53.21
2014	53.077
2015	52.912
2016	50.804
2017	50.803
2018	50.76
2019	50.695
2020	50.629
2021	50.557
2022	50.49