Distribution of the N_H values as a function of the L_{2−10 keV}/L_[OIII] ratio. Color- and shape-coding as in Fig. 1. The solid lines represent the mean N_H vs. L_{2−10 keV}/L_[OIII] relation followed by the Seyfert-1 sample in Akylas & Georgantopoulos (2009) assuming a photon index of 1.8 and 3% (thin line: 1%) reflected radiation (see also Maiolino et al. 1998; Cappi et al. 2006), while the dashed lines represent the ±3σ dispersion. The numbers of interesting sources correspond to the sequence numbers in Tables 1 and 2.