Year	Percent
1980	47.1895
1982	51.67414
1984	56.3363
1991	59.31075
1992	69.16595
1993	71.53881
1994	73.04582
1995	68.41807
1996	73.47738
1997	73.28404
1998	67.8227
2003	79.43318
2005	80.32614
2006	86.4537
2008	86.36084
2009	88.35797
2010	92.78649
2011	94.75138
2012	93.84786
2013	86.4135
2014	81.53817
2015	81.58035
2016	83.93665