There are about 77,000 people known to have cystic fibrosis. That's from the various cystic fibrosis registries available globally. The World Health Organization suggests that this number may be low, because there's no reporting on cystic fibrosis from the developing world. The accepted number, at the moment, is about 80,000. That's the one that is used for most of the work that's being done on cystic fibrosis.