Year	Percent
1982	46.85
1996	44.27
2005	44.85
2006	45.08
2007	45.09
2008	46.47
2009	47.34
2010	48.57
2011	48.42
2012	47.59
2013	47.38
2014	48.34
2015	49.43
2016	50.13
2017	50.37