73% (1986)

74% (1990)

71% (1988)

70% (1989)

70% (1990)

69% (1985)

67% (1987)

58% (1986)

69% (1983)

58% (1993)

63% (1991)

66% (1984)

64% (1982)

10% (1996)

57% (1987)

60% (1995)

51% (1982)

45% (1987)

69% (1981)

47% (1993)