58% (1980)

51% (1983)

43% (1982)

46% (1988)

45% (1969)

44% (1961)

53% (1980)

49% (1986)

41% (1976)

49% (1982)

43% (1961)

57% (1973)

53% (1979)

22% (1968)

56% (1987)

54% (1985)

32% (1985)

25% (1964)

48% (1975)

40% (1980)