  Supernova remnants (SNRs) are thought to be the most promising sources of
Galactic cosmic rays. One of the principal questions is whether they are
accelerating particles up to the maximum energy of Galactic cosmic rays ($\sim$
PeV). In this work, a systematic study of gamma-ray emitting SNRs is conducted
as an advanced study of Suzuki et al. 2021. Our purpose is to newly measure the
evolution of maximum particle energies with increased statistics and better age
estimates. We model their gamma-ray spectra to constrain the
particle-acceleration parameters. Two candidates of the maximum energy of
freshly accelerated particles, the gamma-ray cutoff and break energies, are
found to be well below PeV. We also test a spectral model that includes both
the freshly accelerated and escaping particles to estimate the maximum energies
more reliably, but no tighter constraints are obtained with current statistics.
The average time dependences of the cutoff energy ($\propto t^{-0.81 \pm
0.24}$) and break energy ($\propto t^{-0.77 \pm 0.23}$) cannot be explained
with the simplest acceleration condition (Bohm limit), and requires shock-ISM
(interstellar medium) interaction. The average maximum energy during lifetime
is found to be $\lesssim 20$ TeV $(t_{\rm M}/1~{\rm kyr})^{-0.8}$ with $t_{\rm
M}$ being the age at the maximum, which reaches PeV if $t_{\rm M} \lesssim 10$
yr. The maximum energies during lifetime are suggested to have a variety of
1.1--1.8 dex from object to object. Although we cannot isolate the cause of
this variety, this work provides an important clue to understand the
microphysics of particle acceleration in SNRs.
