Year	Percent
1995	50.43358
1996	52.59955
1997	51.9642
1998	52.56264
1999	53.77804
2000	53.51026
2001	53.84442
2002	54.44427
2003	55.20448
2004	54.58221
2005	55.81558
2006	55.97385
2007	57.06516
2008	57.32945
2009	58.06317
2010	58.66713
2011	58.95371
2012	58.36786
2013	58.41964
2014	58.82144
2015	58.64933
2016	58.77944
2017	58.53083