  We analyze the emission in the 0.3-30 GeV energy range of Gamma-Ray Bursts
detected with the Fermi Gamma-ray Space Telescope. We concentrate on bursts
that were previously only detected with the Gamma-Ray Burst Monitor in the keV
energy range. These bursts will then be compared to the bursts that were
individually detected with the Large Area Telescope at higher energies. To
estimate the emission of faint GRBs we use non-standard analysis methods and
sum over many GRBs to find an average signal which is significantly above
background level. We use a subsample of 99 GRBs listed in the Burst Catalog
from the first two years of observation. Although mostly not individually
detectable, the bursts not detected by the Large Area Telescope on average emit
a significant flux in the energy range from 0.3 GeV to 30 GeV, but their
cumulative energy fluence is only 8% of that of all GRBs. Likewise, the
GeV-to-MeV flux ratio is less and the GeV-band spectra are softer. We confirm
that the GeV-band emission lasts much longer than the emission found in the keV
energy range. The average allsky energy flux from GRBs in the GeV band is
6.4*10^-4 erg cm^-2 yr^-1 or only 4% of the energy flux of cosmic rays above
the ankle at 10^18.6 eV.
