Bitcoin mining difficulty dropped 5.7% on Thursday in the largest negative adjustment for nearly 18 months.

The difficulty adjustment came at block height 842,688, falling to 83.1 trillion, according to Bitbo data. It marks the highest negative adjustment since the bear market lows, when difficulty fell 7% on Dec. 6, 2022, and bitcoin was trading for around $17,000.

Bitcoin mining difficulty is a relative measure of how hard it is to mine a new block compared to the easiest it can ever be. It adjusts automatically every 2016 blocks — roughly two weeks — to ensure that, on average, a new block is found every 10 minutes, regardless of how many miners are actively mining.

When there’s an increase in the number of miners, the difficulty of mining bitcoin rises. Conversely, if there is a …