background radiation

Question 1

what are more significant different types of background radiation?

Answer 1

radon gas (50%)
medical treatments (14%)
ground (14%)
food and drink (11.5%)

Question 2

what are less significant different types of background radiation?

Answer 2

cosmic radiation (10%)
testing of nuclear weapons (0.2%)
plane travel (0.2%)
nuclear power stations (0.1%)