  We consider the problem of finding the density of 1's in a configuration
obtained by $n$ iterations of a given cellular automaton (CA) rule, starting
from disordered initial condition. While this problems is intractable in full
generality for a general CA rule, we argue that for some sufficiently simple
classes of rules it is possible to express the density in terms of elementary
functions. Rules asymptotically emulating identity are one example of such a
class, and density formulae have been previously obtained for several of them.
We show how to obtain formulae for density for two further rules in this class,
160 and 168, and postulate likely expression for density for eight other rules.
Our results are valid for arbitrary initial density. Finally, we conjecture
that the density of 1's for CA rules asymptotically emulating identity always
approaches the equilibrium point exponentially fast.
