59% (1980)

50% (1983)

43% (1974)

47% (1960)

40% (1973)

53% (1980)

46% (1980)

52% (1976)

40% (1980)

36% (1981)

44% (1961)

27% (1964)

53% (1985)

49% (1986)

45% (1988)

46% (1980)

52% (1982)

49% (1985)

49% (1982)

47% (1989)