69% (1990)

71% (1988)

73% (1986)

70% (1989)

74% (1990)

69% (1985)

58% (1986)

57% (1987)

69% (1983)

69% (1981)

10% (1996)

67% (1987)

67% (1989)

60% (1995)

63% (1991)

51% (1990)

67% (1984)

64% (1982)

45% (1987)

60% (1987)