> On another note, 3-4 years ago I had access to a large anonymized bank/credit card transaction database from a well known company. It had about 1-2% of all tr

> On another note, 3-4 years ago I had access to a large anonymized bank/credit card transaction database from a well known company. It had about 1-2% of all transactions in the US by our estimates. When we modeled the quarterly sales of Walmart compared to it we found that it was incredibly accurate going back 5 years, even with 1/50th of the US population I used to work for an Australian consultancy "Quantium" who are doing exactly this and scale transaction data using national statistics data [1] - page 13 [1] http://blog.abs.gov.au/Blog/natstats.NSF/dx/Wade%20Tubman.pdf/$file/Wade%20Tubman.pdf http://blog.abs.gov.au/Blog/natstats.NSF/dx/Wade%20Tubman.pd...