According to a recent report published by the Walk Free Foundation, 35.8 million people are trapped in modern slavery.
India, China and Pakistan are the three countries with the largest absolute number of people living in slave-like conditions, while Mauritania, Uzbekistan and Haiti see the highest prevalence of modern slavery in relative terms. In Mauritania 4% of the population are estimated to live in modern slavery.
This chart shows the countries with the largest estimated number of people living in modern slavery in 2014.
You will find more statistics at Statista