Some 30 million people worldwide are victims of sex trafficking, debt bondage, forced labor and other forms of modern slavery, a global index on slavery showed on Thursday.
Here are key facts on the 10 countries with the highest prevalence of slavery per head of population, according to the Global Slavery Index 2013 by Walk Free, an Australia-based rights group.
* Some 151,000 people or almost 4 percent of the population are thought to be slaves, according to the index. Estimates by other groups put the prevalence rate at up to 20 percent.
* Most common is chattel slavery, meaning that slave status is passed down through generations.
* Slavery has been outlawed in Mauritania since 1961 and trafficking since 2003. Forced marriage and debt bondage are not criminalized.
* Haiti has around 209,000 slaves, fueled by high poverty, lack of access to social services and a system of child labor known as "restavek", in which poor children from rural areas are sent to work with families in cities.
* Rights groups say restavek children are often deprived of food, sleep and schooling and are physically, mentally and sexually abused.
* A draft law on human trafficking is now before parliament that would make child trafficking a criminal offense.
* Some 2.1 million Pakistanis are thought to be enslaved, especially children and bonded laborers.
* The Asian Development Bank estimates that 1.8 million are in bonded labor, though some non-governmental organizations put the number far higher.
* Many Pakistanis migrate to Gulf states, Iran, Turkey, South Africa and elsewhere in search of work, where they fall prey to unscrupulous labor agents who withhold passports and don't pay wages.
* With an estimated 13.9 million slaves, India is home to almost half the world's slave population.
* Almost all forms of slavery are prevalent, ranging from inter-generational bonded labor to sex trafficking, child labor and forced marriage.
* Experts say India has excellent anti-slavery laws but enforcement is sporadic and inconsistent. It remains one of the few nations not to have ratified the Worst Forms of Child Lab our Convention.
* An estimated 259,000 Nepalis are enslaved, both