CT: If I'm not mistaken, I thought you once captured the Bitcoin price via BitcoinAverage. Now I see you are doing your own calculations.
G: That's correct. BitcoinAverage is a great resource, but there were a couple of times were BitcoinAverage's API glitched and reported highly inflated prices resulting in a "fun" data cleanup task. It's not good to be reliant on a single data source for such an important data point. Also, it seems that they don't include data from some of the lesser known exchanges.
http://cointelegraph.com/news/115160/coinmarketcap-about-40-of-the-coins-ever-added-to-the-site-are-now-inactive