Year	Percent
1948	2
1949	2
1950	2
1951	2
1952	2
1953	2
1954	2
1955	2
1956	2
1957	2
1958	2
1959	2
1960	2
1961	2
1962	2
1963	2
1964	2
1965	3
1966	3
1967	3
1968	3
1969	3
1970	4
1971	4
1972	4
1973	5
1974	8
1975	7
1976	7
1977	13
1978	18
1979	18
1980	18
1981	18
1982	19
1983	25
1984	25
1985	19
1986	16
1987	15
1988	14
1989	15
1990	15
1991	20
1992	22
1993	11
1994	9
1995	9
1996	7
1997	5
1998	3