56% (1988)

53% (1982)

52% (1987)

55% (1987)

62% (1988)

56% (1971)

50% (1974)

52% (1984)

42% (1978)

63% (1984)

68% (1985)

60% (1977)

56% (1986)

55% (1988)

57% (1986)

54% (1974)

63% (1979)

50% (1971)

57% (1984)

59% (1985)