Year	Percent
1948	5
1949	5
1950	5
1951	6
1952	6
1953	6
1954	6
1955	7
1956	7
1957	8
1958	7
1959	7
1960	7
1961	7
1962	7
1963	6
1964	7
1965	5
1966	5
1967	6
1968	6
1969	6
1970	6
1971	5
1972	4
1973	9
1974	9
1975	7
1976	7
1977	4
1978	4
1979	6
1980	7
1981	6
1982	6
1983	5
1984	5
1985	5
1986	3
1987	3
1988	3
1989	4
1990	6
1991	5
1992	3
1993	2
1994	2
1995	1
1996	1
1997	1
1998	1
1999	1
2000	1
2001	0
2002	0
2003	0
2004	0
2005	0
2006	0