Year	Percent
1995	70.38139
1996	72.30659
1997	71.24509
1998	70.2246
1999	72.03275
2000	72.10597
2001	72.82183
2002	73.1345
2003	72.90585
2004	72.71997
2005	73.75192
2006	75.75978
2007	74.22284
2008	76.01523
2009	77.83595
2010	78.2681
2011	78.30612
2012	78.25692
2013	78.12521
2014	77.59954
2015	78.97926
2016	78.64705
2017	78.92966