42% (1976)

68% (1971)

60% (1978)

55% (1987)

57% (1975)

52% (1979)

51% (1978)

45% (1978)

51% (1969)

61% (1970)

61% (1970)

48% (1977)

64% (1971)

66% (1977)

55% (1988)

75% (1971)

53% (1988)

73% (1972)

56% (1971)

50% (1971)