52% (1973)

39% (1970)

43% (1969)

37% (1970)

32% (1973)

20% (1975)

40% (1969)

26% (1968)

20% (1970)

45% (1971)

30% (1972)

41% (1970)

20% (1974)

10% (1971)

45% (1975)