  A large number of complete fusion excitation functions of reactions including
the breakup channel were measured in recent decades, especially in the last few
years. It allows us to investigate the systematic behavior of the breakup
effects on the complete fusion cross sections. To this end, we perform a
systematic study of the breakup effects on the complete fusion cross sections
at energies above the Coulomb barrier. The reduced fusion functions F(x) are
compared with the universal fusion functions which are used as a uniform
standard reference. The complete fusion cross sections at energies above the
Coulomb barrier are suppressed by the breakup of projectiles. This suppression
effect for reactions induced by the same projectile is independent of the
target and mainly determined by the lowest energy breakup channel of the
projectile. There holds a good exponential relation between the suppression
factor and the energy corresponding to the lowest breakup threshold.
