The Population Reference Bureau, a private research organization, has released their 2010 World Population Data Sheet. PRB prepares this research annually, and it contains a wealth of data on demographic measurements for every country in the world, along with commentary that highlights significant trends.
PRB's commentary this year points out two major demographic issues that exist globally:
""On the one hand, chronically low birth rates in developed countries are beginning to challenge the health and financial security of their elderly. On the other, the developing countries are adding over 80 million to the population every year and the poorest of those countries are adding 20 million, exacerbating poverty and threatening the environment."
Here are the countries in 2010 with the largest percentages of the population over the age of 65, per PRB's data:
The imbalance in population growth rates between developed countries and the rest of the world would seem to indicate that migration could help mitigate the economic problems caused by shrinking workforces on the one hand and difficulties generating enough growth to provide jobs for workers on the other hand. Political and cultural considerations result in significant barriers to migration, of course.
Key metrics that are included in the data sheet for each country include estimated 2010 population, rate of natural increase, total fertility rate, and projected population for 2025 and 2050.