Distribution of total residuals on occultation astrometry (quadratic sum of AC and AL residuals), obtained by fitting the astrometry derived by occultations only, as a function of the number of chords. All occultations have been reduced by adopting stellar positions available in Gaia EDR3. A few events with stars not in Gaia EDR3 have not been considered. Top panel: residual in mas. Bottom: residual normalised to the apparent asteroid radius at the epoch of the event.