8.33% is the chance of rolling a 10 exactly! If you switch the Data option from "Normal" to "At least", you'll see the probabilities for rolling equal to or above a given number. The cumulative probabilities of rolling 10, 11, and 12 (8.33, 5.56, and 2.78 respectively) add up to 16.67 - or 16.7, if you wanna round it.
It's possible we've made a mistake on Anydice (and if so, thank you for pointing out a balancing error in the game), but these results seem to check out:
