Year	Percent
2000	65.14
2001	66.73
2002	66.13
2003	67.66
2004	68.3
2005	68.06
2006	69.63
2007	71.86
2008	72.65
2009	73.52
2010	73.15
2011	74.31
2012	76.67
2013	76.85
2014	77.73
2015	78.58
2016	78.87
2017	79.17