The age structure of a population makes considerable difference in what that population can do. A high dependency ratio in a poor country often produces something similar to what has been called the low income trap. Kenya represents a common problem for the less developed regions. The rapid decline in mortality in the 1950s increased the young population to near half of the total, giving it a very high dependency ratio, which does not yet show signs of declining. Mauritius and South Korea show what happens to a poor, less developed region when it first experiences rapid mortality decline, but then follows this with rapid fertility decline. Mauritius experienced an increase in its dependency ratio to 103 in 1960, and a steady decline to the Swedish level after that. South Korea never reached the 100 mark, and its rapid fertility decline brought the dependency ratio to a low of 49 in 1990.