Year	Percent
1972	53.55307
1973	51.92341
1975	77.77425
1976	77.69828
1977	72.74716
1978	71.22121
1979	76.92821
1980	74.72176
1981	76.53238
1982	79.31614
1983	81.07135
1984	70.79586
1987	66.7142
1988	66.09886
1989	66.45088
1992	62.91981
1995	66.02302
1996	68.26289
1997	69.38939
2002	75.46744
2003	73.40788