Year	Percent
1948	4
1949	4
1950	4
1951	5
1952	5
1953	5
1954	5
1955	5
1956	5
1957	5
1958	5
1959	5
1960	6
1961	6
1962	6
1963	6
1964	6
1965	5
1966	5
1967	5
1968	5
1969	5
1970	5
1971	5
1972	5
1973	6
1974	7
1975	7
1976	7
1977	14
1978	17
1979	26
1980	28
1981	28
1982	28
1983	22
1984	17
1985	30
1986	21
1987	49
1988	24
1989	38
1990	21
1991	21
1992	17
1994	5
1995	6
1996	6
1997	7
1998	9
1999	10
2000	12
2001	12
2002	8
2003	8
2004	10
2005	12
2006	15