59% (1980)

53% (1980)

52% (1976)

56% (1973)

44% (1982)

42% (1961)

41% (1976)

45% (1971)

52% (1982)

53% (1985)

45% (1969)

50% (1983)

43% (1974)

53% (1979)

49% (1985)

45% (1988)

56% (1987)

46% (1980)

43% (1986)

38% (1973)