References for Demographics, general statistics and Wealth in the world

Tweet Government census and statistics agencies
US census bureau
US stats
Statistics Canada
List of international statistics agencies

the Economist magazine, EIU publications and Economist Intelligence Unit

Studies on Wealthy people in the world
World Wealth Report 2005 by Merrill Lynch and Cap Gemini

High-Net-Worth Wealth Grows Strongly at Over 8 Percent, Surpassing $30 Trillion in 2004, According to Merrill Lynch and Capgemini

World Wealth Report 2005 the number of “Millionaires” Grows by over 7% to 8.3 million worldwide

Forbes Magazine