April 19, 2015. Difficulty fell by -3.71% to 47.61B from 49.45B.
Change
-3.71%
New difficulty
47.61B
Period length
14.5 days
Network hashrate then (7-day)
0.3 EH/s
Bitcoin price then
$223
Hashprice then
$2,416/PH/day
The 2,016 blocks before it took 14.5 days, longer than the 14 intended, so hashrate had fallen, and difficulty fell by 3.71%: an ordinary adjustment. For every machine on the network that is a pay rise of the same size until the next retarget.