Distribution of (top plot) and (bottom plot) as a function of the lens redshift for the COSMOS lenses (red stars) and the SLACS lenses (black crosses). In each plot, the lower panel displays a re-binned version of the upper plot using the the median of the ratios in different bins (SLACS bins: z < 0.2 (32 galaxies), 0.2 ≤ z < 0.3 (23 galaxies), 0.3 ≤ z < 0.5 (9 galaxies); COSMOS bins: 0.30 ≤ z < 0.42 (7 galaxies), 0.42 ≤ z < 0.89 (7 galaxies), 0.89 ≤ z < 1.30 (6 galaxies).