57% (1975)

42% (1976)

60% (1978)

55% (1987)

51% (1978)

68% (1971)

45% (1978)

51% (1969)

52% (1979)

66% (1977)

54% (1988)

64% (1971)

61% (1970)

48% (1977)

61% (1970)

50% (1971)

62% (1964)

55% (1988)

56% (1971)

0% (1979)