Year	Percent
1977	60.99796
1978	64.85733
1979	90.9699
1980	92.56126
1981	78.69568
1982	69.54868
1983	60.56534
1984	68.38699
1985	59.95191
1986	59.21679
1987	61.33845
1988	68.7843
1989	78.40912
1990	80.53533
1991	70.00698
1992	65.30372
1993	61.01491
1994	62.79609
1995	64.40899
1996	61.36748
1997	70.32745
1998	66.62463
1999	67.45055
2000	54.51245
2001	48.30648
2002	46.26488
2003	44.94159
2004	46.45805
2005	53
2006	50.94877
2007	56.08574
2008	62.70805
2009	54.07478
2010	53.56534
2011	52.85301
2012	51.4153
2013	48.54041
2014	63.90628
2015	58.80643
2016	53.984
2017	56.20926