The same line of reasoning applies to the more realistic situation where incomes are very unequally distributed, although not perfectly unequal as in our example. Taking the figures from Table 5.1, where we divided the population into quintiles that received 5%, 9%, 13%, 22%, and 51% income shares, respectively, we found that these income shares are a measure of the relative economic welfare of each income class and that the rate of income growth in each quintile is a measure of the economic welfare growth of that class. We can approximate the growth in the total welfare of society as the simple weighted sum of the growth of income in each class. This is in fact what the rate of GNI growth measures the weights applied to each income class are their respective shares of national income. To be specific, in the case of a population divided into quintiles according to rising income levels, we would have