Year	Percent
1971	55.71559
1972	59.23066
1973	68.66804
1974	56.82407
1975	66.25108
1976	68.63913
1977	71.41977
1978	71.77421
1979	78.62537
1980	79.54596
1981	77.85391
1982	77.16315
1983	70.87151
1984	73.98936
1985	71.35406
1986	72.38435
1987	72.85674
1988	73.32994
1989	67.65625
1990	58.80952
1991	54.36378
1992	61.58241
1993	63.00192
1994	53.59834
1996	48.97301
1999	31.18338
2001	56.24172
2002	59.0997
2003	55.80592
2004	80.33339
2005	70.01722
2006	75.80953
2007	73.95279
2008	68.587
2009	67.56606
2010	67.38629
2011	73.70126
2012	70.30071