Left: relation between the specific SFR (sSFR = SFR/M_∗) and the stellar mass (M_∗) at various redshifts. Our z = 1 stacked measurements from S15 are shown with empty diamonds, and the average values of the star-forming HRS galaxies are shown with empty circles. The associated error bar is the error on the mean, not the dispersion of the sample. We compare these measurements to the z = 2 values obtained by Magdis et al. (2012) for star-forming BzK galaxies. Right: same as left, but replacing the sSFR by the star formation efficiency (SFE = SFR/M_gas). The diamonds and circles use the gas mass estimated in this paper, while the empty squares come from Magdis et al. (2012) and were computed with the same method. We also show for reference the measurements of Saintonge et al. (2011b) with empty gray circles. Their study only included H₂ in M_gas, therefore we rescaled their measurement to include H i assuming R_mol = log ₁₀(M_H2/M_{H i}) = 0.425 (log ₁₀(M_∗/M_⊙)−10.7)−0.387 (Saintonge et al. 2011a, Fig. 9 and Table 4). We also caution that the sample selection in Saintonge et al. (2011b) is different from ours.