Two-dimensional histograms of radio loudness (ℛ) versus Eddington ratio (λ) for radio Seyfert and OPARG objects (a) and radio Seyfert, OPARG, and OPIRG objects combined (b). Bin colours represent the logarithm of the number of objects, as indicated by the colour bars. Marginal 1D histograms of radio loudness are shown on the right-hand side of each panel. Values with and without a prime indicate L_bol derived solely from [O III] or from a mix of [O III] (for OPARG and Seyfert) and W3 (for OPIRG) luminosities, respectively. The number of objects is indicated in each panel. The dashed line corresponds to the classical radio-loudness threshold of Kellermann et al. (1989), and the dotted line to the division from Gupta et al. (2018); both are shown using our convention. No bimodality is seen in either the 1D or 2D histograms.