Lorenz curve: Essentially the graphical representation of cumulative distribution of the variable, most often used for the income. If the risks of disease are not monotonically increasing as the exposure becomes heavier, the data have to be arranged again from the lowest to the highest risk before the calculation of cumulative percentages. Associated with such type of curve is the Gini index defined as twice the area between curve and diagonal line. This index is lies between zero and one, with the larger values indicating the larger variability while smaller ones signify larger uniformity. The further the Lorenz curve lies below line of equality, the more unequal is the distribution of, the figure for this is given below