I've played with mining a bit and started wondering how profitable mining has been historically. I pulled some data on the Blockchain and from Gox to see closing prices and difficulty at the time - graphed prices and difficulty separately, then another that is Price / Difficulty * 1,000,000 (to make the numbers easier to read).
https://docs.google.com/spreadsheet/ccc?key=0AnrzSC4C8ZZedEN3SFl3UEp4YnVpNzdEemNJb2hwWnc&usp=sharingThis all ties into the argument that it's often better to buy bitcoins rather than investing in mining hardware, as the value of bitcoins purchased now will likely exceed the ROI from mining hardware.. For example: I purchased a BFL Jally 7+gh at $274 shipped (maybe not the best example, but it's mine!) - That price tag could have bought me 2+ BTC at the time. Now the Jally will only likely mine 1 BTC meaning my ROI is less than half of what it would have been.
Anyhow - I just wanted to see Difficulty / Price over time, and now you can too!
I have data dating back to 2009, but getting reliable pricing that far back is impossible.. Remember - these are Mt.Gox closing prices.
Data is from:
http://bitcoincharts.com/charts/mtgoxUSD [using the raw data export]
http://blockexplorer.com/q/nethash Used (time1-time2)/24/60/60 to get 'Days Passed' then added them up starting at 1/10/2009 (Approx block 288).. Then A little more magic to strip out time