80% (1984)

78% (1987)

35% (1986)

50% (1988)

60% (1985)

56% (1987)

50% (1987)

60% (1986)

80% (1988)

55% (1986)

47% (1987)

50% (1981)

60% (1981)

58% (1984)

52% (1985)

30% (1981)