↑ ถึง 2014[update], BTC is a commonly used code.[17] It does not conform to ISO 4217 as BT is the country code of Bhutan, and ISO 4217 requires the first letter used in global commodities to be 'X'.
↑ Relative mining difficulty is defined as the ratio of the difficulty target on 9 January 2009 to the current difficulty target.
↑ It is misleading to think that there is an analogy between gold mining and bitcoin mining. The fact is that gold miners are rewarded for producing gold, while bitcoin miners are not rewarded for producing bitcoins; they are rewarded for their record-keeping services.[48]
↑ The exact number is 20,999,999.9769 bitcoins.[43]:ch. 8
