In case you were curious, I just finished doing the numbers on last week's episode of Critical Role. Out of the 15 times Wil rolled, 11/15 were 10 or below (4 of those were Nat1s), and the remaining 4/15 were modified 18, 20, 16, and 19, respectively.
Those numbers include ALL dice rolls he rolled over the night, including the negated Nat1 and the 19 he rolled at the end of the night. NOT including the nat1 nor the 19, he rolled 23% 1s, 23% useful die rolls, and 77% failing rolls below 10.
wilwheaton: "Suck on THAT, probability!"