As Bitcoin miners leave China totally, the hardness of extracting Bitcoins will be reduced and will likely be at the same level as last year. Estimates show that this hardness decreases by 21%. However, double-digit changes in Bitcoin network stiffness are rare, and this reduction is perhaps the largest change in the history of Bitcoin hardness. Miners' revenue fell sharply to $ 23 million a day, down 64.5 percent from a peak in May.