Bitcoin hash rate has recently surpassed a major milestone. The hash rate miners are deploying on the network moved above the 100 EH/s mark according to the node of Blockchain.info. The hash rate deployed on Bitcoin has doubled since May. The difficulty level of mining adjusts every 2016 blocks (approximately two weeks) based on how much hash rate has been deployed. Kevin Rooke has pointed out that the difficulty level of mining on Bitcoin has been increasing an average of 42% per quarter over the past three years.
Source: Blockchain.info