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Population Growth and Income Growth

25 April, 2016 - 09:12

On a simplistic level, the relationship between growth in population and growth in per capita income is clear. After all, per capita income equals total income divided by population. The growth rate of per capita income roughly equals the difference between the growth rate of income and the growth rate of population. Kenya’s annual growth rate in real GDP from 1975 to 2005, for example, was 3.3%. Its population growth rate during that period was 3.2%, leaving it a growth rate of per capita GDP of just 0.1%. A slower rate of population growth, together with the same rate of GDP increase, would have left Kenya with more impressive gains in per capita income. The implication is that if the developing countries want to increase their rate of growth of per capita GDP relative to the developed nations, they must limit their population growth.

Figure 33.2 plots growth rates in population versus growth rates in per capita GDP from 1975 to 2005 for more than 100 developing countries. We do not see a simple relationship. Many countries experienced both rapid population growth and negative changes in real per capita GDP. But still others had relatively rapid population growth, yet they had a rapid increase in per capita GDP. Clearly, there is more to achieving gains in per capita income than a simple slowing in population growth. But the challenge raised at the beginning of this section remains: Can the world continue to feed a population that is growing exponentially—that is, doubling over fixed intervals?

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Figure 33.2 Population and Income Growth, 1975–2005
A scatter chart of population growth rates versus GNP per capita growth rates for various developing countries for the period 1975–2005 suggests no systematic relationship between the rates of population and of income growth.

Source: United Nations Development Program, Human Development Report 2007/2008 (New York: Palgrave Macmillan, 2007).