The incidence of non-Hodgkin lymphoma across the world is approximately one case per 10,000 of the adult population. However, there are higher incidences in certain societies and amongst those who are predisposed. See the sections below.
The photo shows a man with a large mass of non-hodgkin's lymphoma nodes in his right armpit (before - left panel of photo) and after (right panel - node mass gone!) successful therapy