50% (1984)

71% (1981)

46% (1980)

48% (1982)

30% (1979)

37% (1983)

55% (1987)

66% (1979)

45% (1987)

40% (1981)

60% (1979)

52% (1978)

50% (1984)

33% (1985)

10% (1952)