Year	Percent
1991	58.16
1992	59.424
1993	59.745
1994	59.162
1995	58.21
1996	57.239
1997	57.078
1998	58.188
1999	58.888
2000	59.893
2001	63.046
2002	61.775
2003	62.122
2004	62.29
2005	63.305
2006	63.389
2007	63.638
2008	63.704
2009	65.258
2010	66.035
2011	66.003
2012	66.539
2013	67.517
2014	68.068
2015	68.344
2016	68.783
2017	68.875
2018	69.117
2019	69.27
2020	69.365
2021	69.473
2022	69.585