Population analysis on the observed targets. Upper panel: observational errors of the chromatic transit depths in unit of scale heights (gray squares) compared with the nominal amplitudes of the sodium D-lines assuming clear atmospheres (yellow dots). Middle panel: posterior distributions of the cloud-top pressures from the retrieved atmospheric models assuming chemical equilibrium. Lower panel: posterior distributions of the scattering factors from the retrieved atmospheric models assuming chemical equilibrium. The error bars indicate the 1σ credible intervals.