  The entropy production in medium energy heavy-ion collisions is analyzed in
terms of ratio of deuteronlike to protonlike clusters ($d_{like}/p_{like}$)
using \emph{quantum molecular dynamics} (QMD) model. The yield ratios of
deuteronlike-to-protonlike clusters calculated as a function of participant
proton multiplicity closely agree with experimental trends. Our model
predictions indicate that full thermodynamical equilibrium may not be there
even for the central geometry. The apparent entropy extracted from the yield
ratios of deuteronlike-to-protonlike clusters, however, reflects the
universality characteristics \emph{i.e.} it is governed by the volume of
reaction independent of the target-projectile combination. Our calculations for
apparent entropy produced in central collisions of Ca+Ca and Nb+Nb at different
bombarding energies are in good agreement with $4\pi$ Plastic Ball data.
