Average gain in RDI 5σ contrast as a function of reference library size used to subtract stellar contributions. RDI contrasts were averaged over all the targets with similar observing conditions, but different seeing conditions (left) or different PA rotations (right). For all the angular separations, RDI contrasts improved with increasing number of reference images and reached plateaus after a library size of ~3000 reference images (~4.5% of all the references).