Direct comparison of the iron-mass fractions between the 26 rocky exoplanets and their host stars. The iron-mass fractions of rocky exoplanets are computed from the interior model using the MCMC method, and the iron fractions of host stars are calculated from stellar elemental abundance ratios using Eq. (2). Different colors denote the equilibrium temperature T_eq of rocky exoplanets. The ODR fitting is performed for the whole sample (dashed lines) and for the sample without the super-Mercuries (solid lines), respectively. Normalized residuals from the fit without super-Mercuries are plotted in the bottom panel.