52% (1976)

42% (1978)

44% (1973)

36% (1977)

52% (1977)

43% (1986)

32% (1982)

30% (1974)

45% (1980)

20% (1981)

39% (1987)

31% (1975)

38% (1978)

33% (1981)

46% (1975)

32% (1983)

32% (1976)

38% (1983)

34% (1983)

55% (1977)