  Covariant density functional theory (CDFT) is a modern theoretical tool for
the description of nuclear structure phenomena. The current investigation aims
at the global assessment of the accuracy of the description of the ground state
properties of even-even nuclei. We also estimate {\it theoretical
uncertainties} defined here as the spreads of predictions within four covariant
energy density functionals (CEDF) in known regions of the nuclear chart and
their propagation towards the neutron drip line. Large-scale axial relativistic
Hartree-Bogoliubov (RHB) calculations are performed for all $Z\leq 104$
even-even nuclei between the two-proton and two-neutron drip lines with four
modern covariant energy density functionals such as NL3*, DD-ME2, DD-ME$\delta$
and DD-PC1. The physical observables of interest include the binding energies,
two-particle separation energies, charge quadrupole deformations, isovector
deformations, charge radii, neutron skin thicknesses and the positions of the
two-proton and two-neutron drip lines. The predictions for the two-neutron drip
line are also compared in a systematic way with the ones obtained in
non-relativistic models. As an example, the data set of the calculated
properties of even-even nuclei obtained with DD-PC1 CEDF is provided as
Supplemental Material with this article (file ddpc1.pdf).
