There are approximately 6,445,757,246 people in the world today. Bill Gates has about $38 billion.
38/6 = $6.33 per person. Lets say only one tenth of the world actually own a computer, That would eqaute to about $63 a person, technically thats about 600million computers running some kind of microsoft software at some point between 1985 - 2005 which is 20 years.
So it is 41 billion or whatever, my figures are exact, but 600million copies over 20 years =
30 million copies a year - or
2.5 million copies a month - or
625,000 copies a week - or
about 89,500 copies a day - or
3279 copies an hour - or
62 copies a minute - or finally
1 copy every second.
copies are priced at around £60-£90
Also bear in mind the intrest in his bank account, the money from advertising, X-box sales, Games, merchandise and so on.