July 22, 2013. Difficulty rose by +19.47% to 31.26M from 26.16M.
Change
+19.47%
New difficulty
31.26M
Period length
11.7 days
Network hashrate then (7-day)
0.0 EH/s
Bitcoin price then
$91
Hashprice then
$1,623,697/PH/day
The 2,016 blocks before it took 11.7 days instead of 14, so the network had more hashrate than the difficulty assumed, and difficulty rose by 19.47%: one of the largest adjustments on record. For every machine on the network that is a pay cut of the same size until the next retarget.