54% (1970)

48% (1972)

58% (1973)

42% (1973)

47% (1972)

71% (1977)

57% (1971)

55% (1973)

44% (1980)

50% (1977)

34% (1960)

50% (1981)

58% (1979)

45% (1975)

25% (1972)

57% (1976)

50% (1981)

56% (1969)

46% (1974)

53% (1968)