What are three trends that have contributed to the rise of modern day slavery?

The first:, a recent population explosion has tripled the number of people in the world, with most growth taking place in the developing world. The second, rapid social and economic change, have displaced many to urban centers and their outskirts, where people have no ‘safety net’ and no job security. The third: government corruption around the world, allows slavery to go unpunished, even though it is illegal everywhere.