77% (1967)

71% (1981)

68% (1980)

74% (1968)

66% (1981)

66% (1971)

71% (1968)

69% (1970)

75% (1970)

57% (1972)

50% (1969)

58% (1980)

59% (1977)

56% (1970)

61% (1973)

56% (1980)

32% (1977)

53% (1982)

45% (1969)

58% (1981)