Year	Percent
1948	2
1949	2
1950	2
1951	2
1952	2
1953	2
1954	2
1955	3
1956	3
1957	3
1958	3
1959	4
1960	3
1961	3
1962	3
1963	4
1964	4
1965	4
1966	5
1967	5
1968	5
1969	6
1970	6
1971	5
1972	5
1973	8
1974	8
1975	6
1976	5
1977	6
1978	10
1979	12
1980	13
1981	12
1982	9
1983	9
1984	8
1985	8
1986	6
1987	6
1988	7
1989	7
1990	7
1991	4
1992	3
1993	3
1994	5
1995	5
1996	5
1997	5
1998	5
1999	5
2000	6
2001	1
2002	1
2003	2
2004	3
2005	5
2006	6