Fun with numbers: Doctor Shortage in Rural America

I received an email doing publicity for an American "international medical school", it's mainly padding but here's the fun part:

Historically, graduates of international medical schools have been far more likely to practice in non-urban areas with primary-care shortages than their U.S.-trained counterparts.

Twenty percent of the U.S. population lives in rural settings; only 10 percent of doctors practice there.

Rural communities have 20 percent fewer doctors per person than their urban counterparts.

How do you get "20 percent fewer" out of that?

In very round figures, USA population = 400 million and 1 million doctors.

Urban = 320 million people; 900,000 doctors = 356 people per doctor
Rural = 80 million people; 100,000 doctors = 800 people per doctor.
That's about 50 per cent fewer doctors per person.

I hope for the sake of America's rural population that the school understands medicine better than they understand maths.