69% (1987)

73% (1988)

60% (1978)

64% (1986)

66% (1990)

67% (1988)

65% (1988)

54% (1980)

61% (1984)

62% (1985)

62% (1975)

63% (1989)

50% (1985)

60% (1985)

63% (1987)

62% (1985)

60% (1984)

53% (1981)

47% (1983)

58% (1980)