February 5, 2013. Difficulty rose by +10.33% to 3.28M from 2.97M.
Change
+10.33%
New difficulty
3.28M
Period length
12.7 days
Network hashrate then (7-day)
—
Bitcoin price then
$21
Hashprice then
—
The 2,016 blocks before it took 12.7 days instead of 14, so the network had more hashrate than the difficulty assumed, and difficulty rose by 10.33%: 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.