This is an instructive case. An illegal population is, by definition, the set of people the state has failed to count, so every official figure is a guess biased downward.
Spain just turned up roughly *double* the official estimate. And Spain is a much easier case: small, its migration influx recent, its borders comparatively much smaller, sea-moated, manageable, etc. A country like America with decades more history of mass illegal migration and a much larger, more porous, barely functioning wide-open-frontier border will obviously run a far wider gap than 2x.
So treat the familiar 10-30 million illegal alien estimate the government has been quoting for years as a lowball and nothing more.
Bovinoβs 100 million estimate is likely closer to the truth:
JUST IN: Spain reveals 900,000 undocumented migrants have applied for legal status under its mass naturalization program β nearly double initial expectations.