Distributions of photon indices and the host-galaxy absorption column densities, These values are always measured using the baseline PL model, irrespective of the true best-fit model for each source. Sources with soft excesses are shown as red squares, sources with warm absorbers are shown with blue circles, sources best fit with partial covering are shown with orange pentagons, and sources best fit with the baseline power law model are shown as black crosses. Marker styles represent samples of different purities, as described in Sect. 3. The typical error bars are shown in the top right corner, and the horizontal grey line indicates a column density of 10²² cm⁻².