Board Thread:Questions and Answers/@comment-26533134-20151013074106/@comment-50.204.243.110-20151119151128

As other have said, % = chance it will level up.

e.g. - you add scrolls and 3/4/5/6* cards to get % to 80% = 80% chance skill will lvl up

e.g. - you add scrolls and 3/4/5/6* cards to get % to 150% = guaranteed +1 lv, and 50% chance of +1 additional lvl up