the condition is very common; about one percent of people worldwide (65 million) have epilepsy. nearly eighty percent of all cases occur in developing countries. epilepsy becomes more common as people age. in the developed world, onset of new cases occurs most frequently in infants and the elderly. in the developing world this is in older children and young adults. between five and ten percent of all people will have an unprovoked seizure by the age of eighty. the chance of having a second seizure is between forty and fifty percent.