71% (1988)

70% (1989)

73% (1986)

69% (1990)

73% (1990)

58% (1986)

69% (1983)

69% (1985)

67% (1987)

64% (1982)

63% (1991)

57% (1987)

69% (1991)

73% (1985)

51% (1990)

51% (1982)

59% (1992)

47% (1993)

45% (1987)

67% (1984)