Normalised cumulative distribution of the AGN fraction measured by SED fitting for the different AGN selection methods in EDFN: C75/R90 (green solid/purple dashed), B24A/B (grey/lime dashed), spectroscopically confirmed broad-line or narrow-line AGN (red dash-dotted/cyan solid), I_EH_gz (yellow solid), JH_I_EY (black dash-dotted), PRF (dark blue dotted, TM25), and X-ray (pink solid,, RW25). The blue dashed-dotted line is the inverse cumulative distribution of all non-AGN candidates. The vertical black solid line represents the proposed AGN fraction threshold (f_AGN = 0.25) discriminating AGN and non-AGN sources, while the horizontal black dotted line shows the corresponding false-positive probability (23%). We note that only two X-ray sources have counterparts with z_spec in the quality-filtered EDF-N catalogue.