Since the 1970s oil boom, the Gulf region has been one of the principal destinations for workers from South Asia, with the result that today Indians constitute a large percentage of the non-nationals living in the region. Indeed, at five million out of an estimated 15 million people, the Indian community forms the largest expatriate group in each of the Gulf countries. Most Indian immigrants are from the south Indian state of Kerala, while many of the rest originate from Tamil Nadu, Punjab, Uttar Pradesh, and Bihar.