Quantile-quantile plot of the radius distribution at different ages. The reference age is taken to be 5 Gyr. The red three-branch stars represent the population of planets without volatiles and with a gas fraction of 20%. The blue open squares show the population of planets with 70% volatiles in the interior and a mean value of f_gas = 13.8% of gas. From top to bottom, the curves correspond to 100 Myr, 500 Myr, 1 Gyr, and 5 Gyr.