  The Bondi accretion rate of black holes in our and nearby galaxies Messier
87, NGC 3115, NGC 1600, and Cygnus A have been determined or constrained using
Chandra or other observations. It, however, remains unknown how much mass from
the Bondi radius reaches each black hole and how much is accreted. We determine
the accretion rate and radiative efficiency for each black hole using two
well-tested empirical relations: one relates a black hole's accretion rate to
its mass and redshift, and the other relates the radiative efficiency to the
Eddington ratio and redshift. We get an accretion rate of ~0.00002 solar mass
per year and radiative efficiency of ~0.9 for Sagittarius A* and an accretion
rate of ~0.09 solar masses per year and radiative efficiency of ~0.68 for NGC
1600; and values in between these extremes for the rest. The derived mass
inflow rate onto each black hole (not the accretion rate) essentially matches
the reported Bondi accretion rate. Thus, the results do not support the ADIOS
and CDAF models, but whether the dissipated energy not reflected in a black
hole's observed luminosity is advected as in the ADAF model remains uncertain.
Furthermore, contrary to current model expectations, the derived radiative
efficiencies are orders of magnitude higher and radiative efficiency increases
as the accretion rate decreases and a BH ages. A physical basis is found
relating the empirical formulation of accretion rate to Bondi accretion.
