That’s according to the third Global Slavery Index from the Walk Free Foundation, an Australia-based human rights group.
The estimate of people born into servitude, trafficked for sex work, or trapped in debt bondage or forced labor is up from 35.8 million in 2014.
Andrew Forrest, founder of Walk Free, says the increase is due to better data collection, although he fears the situation is getting worse, with global displacement and migration increasing vulnerability to all forms of slavery.
Forrest, an Australian mining billionaire and philanthropist, urges businesses to check their supply chains for worker exploitation, saying he found thousands of people trapped in slavery making goods for his company Fortescue Metals Group.
“But I've had some of the biggest entrepreneurs in the world look me in the eye and say I will not look for slavery in case I find it," he says.
Slavery is found in all 167 countries in the index, with India having the largest total number: 18.4 million slaves among its 1.3 billion population. But Forrest says India deserves credit for starting to address the problem.
North Korea ranks as worst in terms of concentration, with one in every 20 people — 4.4 percent of its 25 million people — in slavery and its government doing the least to end it.
Labor trafficking is also believed to be pervasive, if often hidden, in the United States, says The Christian Science Monitor. The paper notes, for example, 38,500 undocumented Spanish-speaking migrants who were victims of trafficking in San Diego County, Calif.