Classification of galaxies in our sample into three categories depending on whether they show positive mean CO-Hα offsets or not and whether there is a significant trend with radius or not. The error bars are smaller than the size of the plotted circles. The solid lines show running means for individual galaxies plotted against radius normalised by R₂₅. All galaxies are barred except for NGC 628, NGC 1385, NGC 2090, NGC 2997, and NGC 4254.