The observed hardness ratio (HR) of GOODS-S X-ray AGNs as a function of redshift. Large red points show PACS detected AGNs and small black points are PACS-undetected AGNs. Objects detected only in the hard(soft) bands have HR = 1 and HR = −1 respectively. The solid black line shows the expected HR for a power-law X-ray spectrum with a typical photon index of Γ = 1.9 and an obscuring Hydrogen column density of N_H = 10²² cm^-2. Dotted vertical lines mark the 4 redshift bins used in this study. The numbers in each bin give the 1σ range in PACS detection fraction (in %) for obscured X-ray AGNs (i.e., those above the solid line – upper set of numbers) and unobscured X-ray AGNs (i.e., those below the solid line – lower set of numbers). A quick examination will reveal that PACS detection fractions of obscured and unobscured AGNs are similar, with only insignificant differences in any given redshift bin.