volume = x in equation 4, number of Bitcoins transacted in each minute
no = N in equation 4, number of Bitcoin transactions per minute
price	 = P in equation 4, Bitcoin price in each minute in USD
r_rate = P^G in equation 4, 	10 Year Treasury Inflation Indexed Security (daily)
tot_btc = B in equation 4, total bitcoin stock in each minute
velocity = V in equation 4, the speed at which bitcoins are transacted (two alternative measures)


size1 and size2 are two additional proxies of the size of bitcoin economy (not in equation 4) - in alternative specifications they can be included as additional controls