64% (1965)

59% (1980)

52% (1980)

53% (1967)

66% (1971)

58% (1971)

67% (1964)

62% (1966)

63% (1975)

56% (1972)

62% (1963)

58% (1970)

48% (1976)

43% (1981)

47% (1979)

44% (1981)

60% (1969)

59% (1978)

57% (1969)

60% (1980)