41% (1978)

41% (1982)

67% (1985)

57% (1972)

62% (1985)

64% (1988)

57% (1976)

46% (1971)

61% (1975)

51% (1971)

65% (1990)

52% (1982)

61% (1988)

47% (1978)

59% (1984)

63% (1987)

63% (1989)

53% (1980)

59% (1987)

54% (1971)