52% (1977)

41% (1978)

52% (1976)

44% (1973)

55% (1977)

32% (1981)

47% (1980)

38% (1978)

41% (1980)

42% (1986)

37% (1977)

31% (1975)

32% (1976)

36% (1983)

44% (1980)

38% (1983)

47% (1964)

20% (1981)

31% (1982)

31% (1984)