71% (1981)

55% (1987)

50% (1984)

46% (1980)

48% (1982)

67% (1979)

38% (1983)

40% (1981)

55% (1978)

30% (1979)

52% (1984)

33% (1985)

45% (1987)

60% (1979)

10% (1952)