2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/124686Various studies have claimed that the fraction of obscured AGN drops with luminosity, but contrary results are also reported. We present our recent studies on the fraction of X-ray obscured quasars in Chandra Deep Fields and in the local universe showing that most quasars in CDFs (at redshift of 1 ~ 4) are obscured and a consistent pattern in the local universe.4 pages, 2 figures, Conference proceedings to appear in "The Central Engine of Active Galactic Nuclei", ed. L. C. Ho and J.-M. Wang (San Francisco: ASP)Astrophysicstext