=IIf(Fields!absenteeismPercentage.Value < 5, "Green",
IIf(Fields!absenteeismPercentage.Value >= 5 And Fields!absenteeismPercentage.Value < 9, "Yellow",
IIf(Fields!absenteeismPercentage.Value >= 9 And Fields!absenteeismPercentage.Value <= 10, "Red", "Black")))