Distribution of asteroid populations in the Solar System is illustrated based on their semi-major axes and eccentricities from the astorb database (lower plot). Upper plot: distribution of the proper motions for the indicated populations (near-Earth asteroids, NEA; Mars-crosser, MC; main belt, MB; Trojans; Centaurs; and Kuiper belt objects, KBO), extracted at a single epoch for all asteroids. The boxplot displays the minimum and maximum values for each population (whiskers), as well as the 25% and 75% quartiles (box edges) and the median proper motion (box center).