  We use hard X-ray data for an "optimal" sample of Seyfert 2 galaxies to
derive the distribution of the gaseous absorbing column densities among
obscured active nuclei in the local Universe. Of all Seyfert 2 galaxies in the
sample, 75% are heavily obscured (N_H > 10^23 cm^-2) and about half are Compton
thick (N_H > 10^24 cm^-2). Intermediate type 1.8-1.9 Seyferts are characterized
by an average N_H much lower than "strict" Seyfert 2s. No correlation is found
between N_H and the intrinsic luminosity of the nuclear source. This N_H
distribution has important consequences for the synthesis of the cosmic X-ray
background. Also, the large fraction of Compton thick objects implies that most
of the obscuring gas is located within a radius of a few 10 pc from the
nucleus.
