  From the data analysis we defined distribution function against the
population on the level of various structure units, namely regions, federal
districts and the country on the whole. We have studied peculiarities of the
distribution function deformation due to the structure units' enlargement.
Using the master equation in the continuous approximation, we obtain the
Fokker-Plank equation for the distribution function with symmetric transition
rates. In addition, we offer a model where transitions only between neighbour
states are possible. Moreover in this case it is proposed the in and out
transition probability rate for any states are different We define condition
for the formal equivalence of both models to the problem that is described by
the stochastic differential equation with additive and multiplicative white
noises. We have analyzed the corresponding Fokker-Plank equation in the Ito and
Stratonovich calculus, and obtained a solution of the Tsallis distribution
type. We demonstrate a comparison of theoretical results with those of the data
analysis on the level a cumulative distributions. We have used the maximum
likelihood method for fitting. The obtained results allow us to attribute the
specific value of the Tsallis distribution nonextensivity parameter to the
empiric curves.
