Linear fit of the e-damping efficiency to the data from panel b of Figure 5, that is, using the gap depths observed from the simulations on the horizontal axis. In panel a we fit the full data, both for the separate values of e/h (coloured dashed lines) and for the full data set combining all eccentricities (black dashed line). In panel b we fit the data in the same way, but considering gap depths of up to 80% (indicated by the dashed red vertical line). In both cases we report the observed slopes of the lines in the top left legend.