76% (1984)

73% (1985)

69% (1986)

69% (1984)

76% (1980)

50% (1984)

65% (1978)

58% (1985)

64% (1989)

63% (1979)

58% (1976)

75% (1989)

76% (1982)

70% (1988)

55% (1985)

66% (1991)

69% (1977)

44% (1992)

61% (1985)

57% (1979)