It is estimated that there are some 50 to 100 million domestic workers worldwide. The vast majority of these workers are young girls and women, and a large percentage of them are migrants. They serve as nannies, housekeepers, cooks, and caregivers who are most densely concentrated in the Middle East and Asia. Since they are often excluded from workers' and laborers' rights schemes, they often suffer from unpaid wages, excessive hours, little time off, and a high frequency of physical and sexual abuse, making them some of the most exploited workers in the world.