64% (1982)

63% (1991)

68% (1987)

61% (1986)

59% (1982)

67% (1983)

63% (1981)

56% (1979)

72% (1987)

73% (1989)

70% (1984)

67% (1985)

62% (1986)

56% (1987)

58% (1988)

57% (1985)

64% (1984)

53% (1985)

61% (1983)

62% (1981)