74% (1981)

55% (1983)

50% (1983)

48% (1989)

60% (1980)

53% (1978)

48% (1976)

43% (1974)

52% (1979)

52% (1979)

56% (1983)

57% (1981)

33% (1976)

48% (1977)

55% (1976)

73% (1973)

58% (1981)

56% (1979)

71% (1980)

48% (1982)