Year	Percent
1957	19
1958	19
1959	19
1960	19
1961	19
1962	19
1963	15
1964	16
1965	16
1966	16
1967	16
1968	16
1969	16
1970	12
1971	13
1972	11
1973	11
1974	13
1975	13
1976	13
1977	13
1978	13
1979	18
1980	20
1981	26
1982	37
1983	61
1984	149
1996	17
1997	13
1998	14
1999	13
2000	10
2001	9
2002	13
2003	8
2004	6
2005	5
2006	5