58% (1976)

58% (1971)

50% (1968)

59% (1974)

71% (1983)

48% (1967)

52% (1980)

58% (1985)

58% (1990)

58% (1963)

61% (1986)

50% (1960)

50% (1980)

56% (1989)

50% (1986)

36% (1974)

72% (1982)

57% (1988)

56% (1977)

60% (1968)