56% (1987)

66% (1977)

57% (1975)

62% (1970)

69% (1971)

42% (1976)

47% (1978)

51% (1978)

59% (1978)

52% (1979)

48% (1977)

58% (1969)

56% (1971)

58% (1970)

64% (1971)

37% (1987)

63% (1964)

54% (1988)

61% (1970)

50% (1971)