May 11, 2016. Difficulty rose by +8.73% to 194.25B from 178.66B.
Change
+8.73%
New difficulty
194.25B
Period length
12.9 days
Network hashrate then (7-day)
1.4 EH/s
Bitcoin price then
$451
Hashprice then
$1,157/PH/day
The 2,016 blocks before it took 12.9 days instead of 14, so the network had more hashrate than the difficulty assumed, and difficulty rose by 8.73%: a large adjustment. For every machine on the network that is a pay cut of the same size until the next retarget.