  The X-ray background (XRB) is due to the aggregate of active galactic nuclei
(AGN), which peak in activity at z~1 and is often modeled as the sum of
different proportions of unabsorbed, moderately- and heavily-absorbed AGN. We
present the summed spectrum of a complete sample of local AGN (the Northern
Galactic Cap of the 58-month Swift/BAT catalog, z<0.2) using 0.4-200keV data
and directly determine the different proportions of unabsorbed, moderately and
heavily-absorbed AGN that make up the summed spectrum. This stacked low
redshift AGN spectrum is remarkably similar in shape to the XRB spectrum (when
shifted to z~1), but the observed proportions of different absorption
populations differ from most XRB synthesis models. AGN with Compton-thick
absorption account for only ~12% of the sample, but produce a significant
contribution to the overall spectrum. We confirm that Compton reflection is
more prominent in moderately-absorbed AGN and that the photon index differs
intrinsically between unabsorbed and absorbed AGN. The AGN in our sample
account for only ~1% of the XRB intensity. The reproduction of the XRB spectral
shape suggests that strong evolution in individual AGN properties is not
required between z~0 and 1.
