69% (1987)

73% (1988)

56% (1975)

57% (1972)

56% (1971)

50% (1971)

60% (1978)

58% (1979)

65% (1988)

67% (1988)

66% (1990)

63% (1986)

62% (1985)

56% (1976)

39% (1972)

57% (1976)

63% (1989)

61% (1984)

61% (1974)

63% (1987)