78% (1967)

71% (1970)

71% (1971)

72% (1970)

56% (1964)

62% (1969)

54% (1970)

53% (1966)

51% (1975)

56% (1965)

57% (1967)

57% (1964)

52% (1969)

60% (1968)

63% (1966)

46% (1971)

68% (1968)

61% (1976)

0% (1967)

54% (1965)