67% (1981)

48% (1984)

44% (1983)

65% (1981)

71% (1979)

63% (1977)

63% (1980)

53% (1985)

62% (1980)

60% (1983)

60% (1987)

63% (1985)

61% (1985)

70% (1984)

60% (1984)

45% (1984)

58% (1988)

46% (1985)

54% (1983)

62% (1982)