The most recent Bitcoin mining difficulty adjustment took place at block height 584,640 on the 9th of July. The adjustment resulted in the Bitcoin mining difficulty reaching a record high of 9.06 trillion with an increase of 14.23% from the last difficulty level. The last increase of such magnitude took place on the 29th of July 2018 when the difficulty increased 14.88%. The last difficulty adjustment also resulted in mining difficulty levels reaching an all-time high.
Source: statoshi.info, BTC.com