  Glitch size and waiting time probability density functions (PDFs) are
estimated for the five pulsars that have glitched most using the nonparametric
kernel density estimator. Two objects exhibit decreasing size and waiting time
PDFs. Their activity is Poisson-like, and their size statistics are
approximately scale-invariant. Three objects exhibit a statistically
significant local maximum in the PDFs, including one (PSR J1341$-$6220) which
was classified as Poisson-like in previous analyses. Their activity is
quasiperiodic, although the dispersion in waiting times is relatively broad.
The classification is robust: it is preserved across a wide range of bandwidth
choices. There is no compelling evidence for multimodality, but this issue
should be revisited when more data become available. The implications for
superfluid vortex avalanche models of pulsar glitches are explored briefly.
