That is really a low number. I can imagine a lot of these people either holding it or selling it and then not reporting taxes because it being a low amount. Also a bummer for bitcoin as it definitely brings it in the blackbook for the government.
It's pretty obvious that Bitcoin users won't want to pay tax if they're dealing with significant amounts of money. With small amounts, you can get away with not declaring it so it's fine. With large amounts, it's just too easy not to pay - sell it for cash, hold and trade it or really most methods that don't involve paying into your bank account won't need taxing. It really raises questions about the legality of Bitcoin if it was more popular as governments might be afraid of a decrease in income.