51% (1973)

43% (1969)

20% (1975)

39% (1970)

37% (1970)

40% (1969)

20% (1970)

26% (1968)

30% (1972)

41% (1970)

45% (1975)

10% (1971)

32% (1973)

20% (1974)

45% (1971)