51% (1977)

49% (1978)

63% (1964)

51% (1972)

51% (1975)

45% (1973)

51% (1988)

45% (1989)

48% (1976)

55% (1969)

49% (1990)

45% (1981)

55% (1980)

59% (1964)

56% (1980)

54% (1967)

64% (1970)

48% (1987)

54% (1968)

47% (1988)