From The Atlantic
''The International Labor Organization (ILO) estimates the number of slaves in the world today at around 21 million. Kevin Bales, of Free the Slaves
-- the U.S. affiliate of the world's oldest human-rights organization,
the U.K.-based Anti-Slavery International -- (and the author of Disposable People: New Slavery in the Global Economy) puts it at 27 million. Siddharth Kara of Harvard's Carr Center for Human Rights Policy says more than 29 million.''