Histograms of the dominant gas ionization mechanisms found from each diagnostic diagram. The three top and the bottom left histograms show the fractions of galaxies classified from the BPT diagrams as SF, AGN (LINER or Seyfert), and composite ([NII] BPT). For the WHAN diagram, the galaxies are classified as retired (RG), SF, strong-AGN (sAGN), and weak-AGN (wAGN). Galaxies that could not be classified in a particular diagram are shown in the histograms as unclassified. The bottom right histogram summarizes the information obtained from all the diagrams, which we divided into four categories: SF, AGN, RG, and inconclusive (INC). Galaxies included in the SF, AGN, and RG groups are those that have the same classification in at least four of the five BPT and WHAN diagrams.