I just took a quick look at the motion correction values for 605 datasets and 20 sites from the Functional Connectome database, and found 5 subjects had more than 3 mm motion, 11 had more than 2 mm motion and 115 had more than 1 mm with the rest at less than 1 mm motion (490 subjects). Of course, these are all normal subjects. You would expect more motion in pediatric, epilepsy, ... subjects.