Distribution of planetary systems in different classes of architecture. Blue bars represent the three biased synthetic populations, and the pink bars represent observed systems. Only the systems with at least three planets remaining after applying the bias are kept for the synthetic populations. The observed systems correspond to systems with at least three known planetary masses (or M_p · sini, with i the inclination of the system), and the same RV semi-amplitude threshold has been applied. The error bars correspond to $1/\sqrt{N}$.