However evidence compiled in 2001 indicates that up to 15% of those in the USA are at risk for this condition, which was once considered a rare event. Researchers say that anaphylaxis can be triggered by food, insect stings, drugs and latex. They found that nearly 10% of the known cases of anaphylaxis were triggered by penicillin, 0.5% to 5% by inset stings and 0.0004% by food. Based on the 1999 US population of 272 million, the population at risk for anaphylaxis from penicillin is nearly 27.2 million, from insect stings is 1.36 million to 13.6 million, while only 1,099 cases of anaphylaxis were caused by food allergy.