76% (1980)

76% (1984)

74% (1985)

69% (1984)

77% (1982)

56% (1985)

62% (1971)

58% (1981)

71% (1980)

70% (1986)

67% (1993)

70% (1977)

66% (1991)

63% (1979)

65% (1978)

58% (1983)

0% (1992)

44% (1992)

50% (1984)

65% (1979)