67% (1981)

43% (1983)

48% (1984)

70% (1979)

62% (1980)

61% (1983)

62% (1980)

66% (1981)

59% (1984)

63% (1985)

70% (1984)

61% (1985)

60% (1987)

63% (1984)

58% (1988)

58% (1982)

58% (1983)

76% (1980)

64% (1983)

54% (1983)