58% (1980)

56% (1991)

69% (2000)

73% (1979)

60% (1991)

77% (1988)

69% (1981)

50% (1981)

69% (1984)

72% (1994)

52% (1986)

70% (1989)

73% (1989)

59% (1984)

62% (1984)

74% (1982)

57% (1995)

41% (1997)

83% (1981)

52% (1996)