Sources: Shaohua Chen and Martin Ravallion, The developing world is poorer than we thought, but no less successful in the fight against poverty, World Bank, August 2008

For the 95% on $10 a day, see Martin Ravallion, Shaohua Chen and Prem Sangraula, Dollar a day revisited, World Bank, May 2008. They note that 95% of developing country population lived on less than $10 a day. Using 2005 population numbers, this is equivalent to just under 79.7% of world population, and does not include populations living on less than $10 a day from industrialized nations.

This figure is based on purchasing power parity (PPP), which basically suggests that prices of goods in countries tend to equate under floating exchange rates and therefore people would be able to purchase the same quantity of goods in any country for a given sum of money. That is, the notion that a dollar should buy the same amount in all countries. Hence if a poor person in a poor country living on a dollar a day moved to the U.S. with no changes to their income, they would still be living on a dollar a day.