  We have selected a group of 100 evolved planetary nebulae (PNe) and study
their kinematics based upon spatially-resolved, long-slit, echelle
spectroscopy. The data have been drawn from the San Pedro M\'artir Kinematic
Catalogue of PNe (L\'opez et al. 2012). The aim is to characterize in detail
the global kinematics of PNe at advanced stages of evolution with the largest
sample of homogenous data used to date for this purpose. The results reveal two
groups that share kinematics, morphology, and photo-ionization characteristics
of the nebular shell and central star luminosities at the different late stages
under study.The typical flow velocities we measure are usually larger than seen
in earlier evolutionary stages, with the largest velocities occurring in
objects with very weak or absent [N II] \lambda 6584 line emission, by all
indications the least evolved objects in our sample. The most evolved objects
expand more slowly. This apparent deceleration during the final stage of PNe
evolution is predicted by hydrodynamical models, but other explanations are
also possible. These results provide a template for comparison with the
predictions of theoretical models.
