Hatzes & Rauer (2016) diagram of exoplanets, showing the bulk density as function of their mass. The open circles are the giant planets defined in our sample and the dots are other planets. We kept as planets only those with a density characterised at a level better than 1σ. The arrows represent the candidates in our sample for which it was only possible to derive an upper limit on their mass (see Table B.4). The vertical bars attached to the arrow are the uncertainties on the densities imposed by the uncertainties on the radii. The dashed line represents the empirical lower envelope density for giant and low-mass planets (see Eq. (5)).