Year	Percent
1980	41.77696
1981	40.73796
1982	45.29617
1983	66.9469
1984	62.24073
1985	69.08356
1986	64.81234
1987	64.24993
1988	60.11475
1989	62.90111
1990	72.94251
1991	57.78694
1992	55.27629
1993	55.2368
1994	53.67316
1995	53.38062
1996	53.11964
1997	50.40472
1998	52.44858
1999	53.85638
2000	47.97682
2001	49.8159
2002	49.38721
2003	48.29273
2004	53.10639
2005	54.79049
2006	48.26692
2007	47.6579
2008	57.61845
2009	56.27697
2010	52.73884
2011	49.96543
2012	50.83891
2013	51.29612
2014	49.39135