68% (1980)

77% (1967)

71% (1981)

69% (1970)

66% (1971)

57% (1980)

66% (1981)

74% (1968)

57% (1980)

62% (1974)

57% (1972)

58% (1981)

54% (1982)

61% (1979)

45% (1970)

59% (1977)

62% (1982)

62% (1974)

58% (1974)

48% (1979)