so 199,312,067,531 / 194,254,820,283 = 1.02603408883565 - 1 = .02603408883565 x 100 = 2.603408883565% which was then rounded to 2.60%
Since a number could be something like 2.5999932% bitcoinwisdom would round it up to 2.60%.
I won't so we can have a case where the winner will not match the rounded number posted by bitcoinwisdom.
Yeah I like it! The matheux (mather? mathor? methematicioux?) in me likes that kind of precision.

Mathematician
https://en.wikipedia.org/wiki/MathematicianI think you were looking for this.
Speaking of math lets do a real world number.
https://blockchain.info/413447 (Main Chain) 2016-05-26 02:00:12 we are here right now
413282 (Main Chain) 2016-05-24 21:23:04 this was first one of this jump
so 166 blocks made
1 day = 144 blocks
4 hours = 24 blocks
40 minutes = 4 blocks
adds to 172 so 166/172-1 =
(-3.488372093023%)while bitcoinwisdom using part of last jump is very much higher
https://bitcoinwisdom.com/bitcoin/difficultyBitcoin Difficulty: 199,312,067,531
Estimated Next Difficulty: 209,085,948,934
(+4.90%) way high compared to real time.
Adjust time: After 1849 Blocks, About 12.1 days
We start at 1116 blocksHashrate(?): 1,523,581,927 GH/s
Block Generation Time(?):
1 block: 9.4 minutes
3 blocks: 28.2 minutes
6 blocks: 56.5 minutes
Updated: 22:5 (3.2 minutes ago)
One thing I think I have learned is asic builders simply play with difficulty numbers ramping up 100 to 300 ph at a time