60% (1961)

56% (1974)

57% (1970)

69% (1970)

61% (1968)

65% (1962)

55% (1980)

62% (1978)

61% (1974)

63% (1977)

69% (1991)

52% (1992)

60% (1973)

65% (1970)

50% (1975)

63% (1970)

56% (1970)

40% (1974)

66% (1968)

49% (1970)