59% (1981)

73% (1976)

65% (1975)

71% (1973)

66% (1977)

65% (1974)

55% (1985)

62% (1980)

70% (1970)

75% (1972)

63% (1984)

62% (1973)

44% (1986)

58% (1983)

63% (1975)

62% (1977)

54% (1979)

58% (1977)

57% (1976)

58% (1977)