Year	Percent
1980	41.74246
1982	46.91591
1984	51.02982
1991	65.306
1992	61.99786
1993	63.57008
1994	65.08491
1995	67.84748
1996	64.81235
1997	65.63169
1998	72.3012
2003	74.6958
2005	74.84577
2006	81.06035
2008	80.88178
2009	83.76586
2010	87.49642
2011	89.33666
2012	87.72422
2013	81.71418
2014	78.02263
2015	79.94949
2016	82.67645