This work analyzes the Gompertz-Pareto distribution (GPD) of personal income,
formed by the combination of the Gompertz curve, representing the overwhelming
majority of the economically less favorable part of the population of a
country, and the Pareto power law, which describes its tiny richest part.
Equations for the Lorenz curve, Gini coefficient and the percentage share of
the Gompertzian part relative to the total income are all written in this
distribution. We show that only three parameters, determined by linear data
fitting, are required for its complete characterization. Consistency checks are
carried out using income data of Brazil from 1981 to 2007 and they lead to the
conclusion that the GPD is consistent and provides a coherent and simple
analytical tool to describe personal income distribution data.Comment: 13 pages, 5 figures, LaTeX. Accepted for publication in "Physica A