Distribution of the maximum apparent velocities β_{app,   max} for sources that have been detected in the γ-ray regime (black line) and for those that have not (gray blocks). We show the distributions for all sources (upper panel), quasars (middle panel), and BL Lacs (lower panel). The insets show the normalized-to-surface-area unity distributions for each case and for apparent speeds up to 30c. We used the kinematic data from Britzen et al. (2008).