The following discussions of societies will often make reference to the number or proportion of older people in the society. Be aware that a society can have a large number of older people, but still have a relatively small proportion of its population in old age. The less developed nations show this pattern. This kind of society will have a high birth rate and a large number of young people. More developed nations will have a low birth rate and a high proportion of older people. Each of these types of societies faces different challenges as they respond to population aging.THE DEMOGRAPHIC TRANSITION