Based on the observed flux ratio F _[0.5−2] /F _[2−10] , assuming an underlying F_ν ∝ ν^-0.8X-ray spectra, we have estimated the hydrogen column density for the sample of Type-2 AGN selected in Sect. 3.2. The shaded region shows the fraction of sources in our sample that have hydrogen column density lower than 10²⁰ cm^-2. As expected, most of the AGN we have selected show signs of absorption in their X-ray spectra.