  The decay rate for a black hole to decay nonperturbatively via tunneling is
shown to be related to the Bekenstein-Hawking black hole entropy $S_{bh}$. This
new physical interpretation of the black hole entropy was presented first in
1988 in this paper. I quote here the relevant statement: ``It should be noticed
that the decay rate of a black hole due to nonperturbative instability is
proportional to $\exp(-S_{bh}$, where $S_{bh}$ is the Bekenstein-Hawking
entropy. This seems to indicate that the Bekenstein-Hawking entropy is the
measure of the ability of a black hole to disappear from our Universe in the
one quantum jump, with the simultaneous production of particles carrying away
its total energy.''
