Year	Percent
1948	4
1949	4
1950	4
1951	3
1952	3
1953	3
1954	3
1955	5
1956	6
1957	6
1958	6
1959	6
1960	9
1961	8
1962	8
1963	8
1964	8
1965	8
1966	8
1967	8
1968	8
1969	8
1970	9
1971	9
1972	9
1973	9
1974	9
1975	9
1976	9
1977	9
1978	10
1979	11
1980	26
1981	32
1982	32
1983	49
1984	52
1985	52
1986	48
1987	45
1988	54
1989	54
1990	45
1991	48
1992	48
1993	48
1994	55
1995	50
1996	50
1997	67
1998	67
1999	60
2000	60
2001	60
2002	55
2003	43
2004	38
2005	23
2006	27