58% (1983)

63% (1982)

52% (1977)

57% (1979)

50% (1976)

54% (1983)

52% (1974)

68% (1979)

52% (1984)

45% (1979)

28% (1985)

47% (1984)

44% (1984)

40% (1976)

35% (1985)

36% (1980)