  We compute the variation of the beaming fraction with the efficiency of high
energy gamma-ray production in the outer gap pulsar model of Romani and
Yadigaroglu. This allows us to correct the fluxes observed for pulsars in the
EGRET band and to derive a simple estimate of the variation of efficiency with
age. Integration of this model over the population of young neutron stars gives
the expected number of gamma-ray pulsars along with their distributions in age
and distance. This model also shows that many of the unidentified EGRET plane
sources should be pulsars, and predicts the gamma-ray fluxes of known radio
pulsars. The contribution of unresolved pulsars to the background flux in the
EGRET band is found to be about 5 %. For an animation of our pulsar model see
http://geminga.stanford.edu/users/ion/home.html .
