First take note of how many atheists live in America then determine the percentages of help.<quoted text>
Pay attention to who makes the biggest impact at disaster relief efforts. Maybe there is a big atheist helping hands group I'm not aware of. Or some scientist colony that gathers truckloads of food for those affected.
The point being, if no one was in a religion, their would be more organizations that were of secular charity.
And I think the Red Cross is probably the largest helpers in disasters besides the government and they are both secular.