Year	Percent
1975	0.65006
1976	0.67729
1977	0.68455
1978	0.69136
1979	0.70871
1981	0.72503
1982	0.72274
1986	0.79952
1990	0.77823
1992	0.76559
1994	0.89794
1997	0.86428
2004	0.96576
2007	0.9788