Year	Percent
1967	7
1968	7
1969	7
1970	7
1971	7
1972	7
1973	7
1974	7
1975	7
1976	7
1977	7
1978	8
1979	8
1980	8
1981	13
1982	15
1983	15
1984	13
1985	13
1986	13
1987	13
1988	16
1989	17
1990	19
1991	20
1992	20
1993	46
1994	22
1995	25
1996	27
1997	32
1998	17
1999	26