55% (1980)

63% (1981)

70% (1981)

63% (1982)

53% (1989)

42% (1989)

50% (1982)

43% (1983)

58% (1990)

54% (1979)

51% (1987)

51% (1988)

54% (1979)

47% (1983)

43% (1992)

55% (1985)

52% (1990)

33% (1988)

49% (1984)

31% (1980)