I don't know about your numbers, except that income does not necessarily imply assets... IIRC, from the survey done for "The Millionaire Mind" (<5, but anyway)

I don't know about your numbers, except that income does not necessarily imply assets... IIRC, from the survey done for "The Millionaire Mind" (<5, but anyway), many people had a family/lifestyle business. Technically, a start-up, but the corner fish n chip shop is probably not the first image evoked by the term. Another significant factor was frugality. A theory: the enforced savings of a startup is a significant factor in the retention of the created wealth.