While no hard data exist, Yawn says the Preventive Task Force has been asked to review significantly more screenings in the past four years.

FORBES: Magazine Article

This is not possible in Iraq because no reliable census data exist.

ECONOMIST: The Iraqi war

" Still, it's hard to understand how Hawking knows the things exist if, as Ferguson notes, "there are no experimental or observational data to support this theory.

FORBES: The Universe and Mrs. Ferguson