By 2050 there will be 35 persons of retirement age for every 100 working-age individuals in the U.S. at current fertility levels, according to the UN.

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The 20 countries where fertility is at or below the level needed to sustain the current population include China, Hong Kong, Macao, North Korea, Iran, Kazakhstan, Singapore, Thailand, Armenia, Cyprus, Georgia, Barbados, Cuba, Guadeloupe, Martinique, Puerto Rico, Saint Lucia, Trinidad and Tobago and Chile.

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If Russia continues to make progress in reducing mortality and if not increasing fertility then at least preventing it from declining, it will likely be able to maintain its current population.

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