  We determine the 22$\mu$m luminosity evolution and luminosity function for
quasars from a data set of over 20,000 objects obtained by combining
flux-limited Sloan Digital Sky Survey optical and Wide field Infrared Survey
Explorer mid-infrared data. We apply methods developed in previous works to
access the intrinsic population distributions non-parametrically, taking into
account the truncations and correlations inherent in the data. We find that the
population of quasars exhibits positive luminosity evolution with redshift in
the mid-infrared, but with considerably less mid-infrared evolution than in the
optical or radio bands. With the luminosity evolutions accounted for, we
determine the density evolution and local mid-infrared luminosity function. The
latter displays a sharp flattening at local luminosities below $\sim 10^{31}$
erg sec$^{-1}$ Hz$^{-1}$, which has been reported previously at 15 $\mu$m for
AGN classified as both type-1 and type-2. We calculate the integrated total
emission from quasars at 22 $\mu$m and find it to be a small fraction of both
the cosmic infrared background light and the integrated emission from all
sources at this wavelength.
