Input measured radiation:
Eating one banana per dayis ? times worseor ? times safer
Sleeping next to a human 8 hours per dayis ? times worseor ? times safer
Dental radiography once per yearis ? times worseor ? times safer
Mammogram once per yearis ? times worseor ? times safer
Radiation near Chernobyl after explosionis ? to ? times worseor ? to ? times safer
Living near a nuclear power stationis ? to ? times worseor ? to ? times safer
Living near a coal power stationis ? times worseor ? times safer
Cosmic radiation (from sky) at sea levelis ? times worseor ? times safer
Terrestrial radiation (from ground)is ? times worseor ? times safer
Natural radiation in the human bodyis ? times worseor ? times safer
Radiation produced by the granite of the United States Capitol buildingis ? times worseor ? times safer
Average individual background radiation doseis ? times worseor ? times safer
Average individual background radiation dose (Australia)is ? times worseor ? times safer
Average individual background radiation dose (America)is ? times worseor ? times safer
New York-Tokyo flights for airline crewis ? times worseor ? times safer
Atmospheric sources (mostly radon)is ? times worseor ? times safer
Total average radiation dose for Americansis ? times worseor ? times safer
Smoking 1.5 packs/dayis ? to ? times worseor ? to ? times safer
Current average limit for nuclear workersis ? times worseor ? times safer
Background radiation in parts of Iran, India and Europeis ? times worseor ? times safer
Lowest clearly carcinogenic levelis ? times worseor ? times safer
Elevated limit for workers during Fukushima emergencyis ? times worseor ? times safer

Reference: Wikipedia

Some measurement sites: