60% (1987)

55% (1985)

58% (1985)

61% (1984)

58% (1985)

52% (1984)

54% (1981)

60% (1982)

64% (1978)

46% (1987)

71% (1988)

64% (1979)

72% (1987)

56% (1986)

49% (1987)

63% (1983)

56% (1987)

62% (1977)

59% (1984)

37% (1987)