Google hit a billion unique per month in May of 2011 and they've spent $21 billion in the last 7 years. Assuming no growth (which is absolutely not the case) th

Google hit a billion unique per month in May of 2011 and they've spent $21 billion in the last 7 years. Assuming no growth (which is absolutely not the case) they've spent an average of $3 per user per year.