The difficulty of mining on the Bitcoin network has reached an all-time high on the latest adjustment which took place on the 27th of June at 2:59 am UTC. The difficulty level has increased to 7.93 trillion, a 7.09% increase from the last difficulty level. The increase is not surprising given the current lucrative conditions miners are experiencing with profitability close to twelve-month highs.
Source: Statoshi.info, BTC.com