Year	%
1973	55.09054
1975	59.45078
1976	73.48269
1977	67.29915
1978	76.88403
1979	70.22207
1980	72.38829
1981	66.83912
1982	67.20757
1983	67.94997
1984	70.84913
1985	59.73945
1986	52.62946
1998	85.48387
1999	68.68891
2000	71.70859
2001	70.46941
2002	91.61411
2003	90.63261
2004	86.86701
2005	93.37317
2006	96.76191
2007	85.39582
2010	86.42372
2011	92.35212
2012	93.33704
2013	94.41595