77% (1975)

60% (1978)

80% (1973)

66% (1974)

52% (1973)

67% (1985)

74% (1982)

57% (1981)

65% (1988)

62% (1977)

59% (1985)

52% (1980)

62% (1974)

49% (1974)

64% (1974)