Left-hand panel: number of revolutions spent by our sample comets per unit area in the asteroidal parts of the (a,e) plane, plotted according to an arbitrary colour scale shown on the right. Right-hand panel: same area of the (a,e) plane, cut into small cells for which the total number of comet orbital revolutions within the cell, as listed, is plotted using the colour scale shown on the right. Only cells occupied by at least two asteroids in the MPC database are plotted.