36% (1988)

33% (1990)

37% (1989)

28% (1989)

35% (1992)

48% (1987)

45% (1987)

48% (1989)

35% (1993)

38% (1989)

37% (1991)

28% (1988)

21% (1989)

46% (1986)

34% (1988)

42% (1992)

25% (1989)

20% (1991)

24% (1989)

41% (1988)