There are an estimated 2 to 3 million undocumented workers in Saudi Arabia.
575,000 illegal workers were deported from the Kingdom in 2012, and an addition 200,000 were deported in the first three months of 2013.
Source: Nandagopal J. Nair, “Saudi Arabia’s crackdown on illegal immigrants is a boon for local businesses,” Quartz, June 24, 2013.