Year	Percent
1991	32.46273
1992	27.49116
1993	30.28623
1994	31.53845
1995	35.02838
1996	58.46382
1997	66.50707
1998	71.96563
1999	74.99461
2000	72.62686
2001	71.89985
2002	74.17846
2003	73.63732
2004	72.63332
2005	70.78543
2006	67.70992
2007	68.8998
2008	66.3096
2009	65.53303
2010	55.25732
2011	46.35192
2012	48.85869
2013	49.23797
2014	48.99664
2015	53.06412
2016	55.10235