58% (1980)

51% (1983)

43% (1974)

49% (1985)

40% (1972)

45% (1978)

56% (1987)

43% (1982)

49% (1982)

34% (1969)

40% (1973)

44% (1961)

50% (1981)

46% (1988)

36% (1981)

54% (1978)

48% (1977)

65% (1980)

25% (1964)

40% (1980)