64% (1971)

71% (1972)

46% (1971)

65% (1951)

53% (1971)

45% (1972)

39% (1973)

44% (1973)

43% (1978)

32% (1970)

53% (1979)

44% (1979)

46% (1973)

54% (1975)

46% (1980)

50% (1970)

50% (1973)

50% (1975)

43% (1977)