Variation in f_AGN with the bulge surplus, as calculated by Eq. (5), for strongly barred (solid red), weakly barred (dashed navy blue), and unbarred (dotted teal) galaxies. The horizontal lines show the mean f_AGN for each bar category. Shaded regions show the 1σ uncertainties. Galaxies at a given stellar mass are more likely to be hosting an AGN if they also have a greater bulge surplus, and this relationship is steeper for unbarred galaxies than for strongly or weakly barred ones.