72% (1981)

65% (1984)

39% (1977)

78% (1976)

47% (1984)

71% (1977)

52% (1978)

51% (1976)

38% (1978)

66% (1976)

54% (1987)

46% (1978)

48% (1995)

65% (1979)

63% (1980)

50% (1981)

60% (1975)

40% (1978)

50% (1979)

58% (1976)