Document 
Eur. Phys. J. B 20, 585-589
Evidence for the exponential distribution of income in the USA
A. Dragulescu and V.M. YakovenkoDepartment of Physics, University of Maryland, College Park, MD 20742-4111, USA yakovenk@physics.umd.edu
(Received 21 August 2000)
Abstract
Using tax and census data, we demonstrate that the
distribution of individual income in the USA is exponential. Our
calculated Lorenz curve without fitting parameters and Gini
coefficient 1/2 agree well with the data. From the individual
income distribution, we derive the distribution function of income
for families with two earners and show that it also agrees well with
the data. The family data for the period 1947-1994 fit the Lorenz
curve and Gini coefficient 3/8=0.375 calculated for two-earners
families.
87.23.Ge - Dynamics of social systems.
89.90.+n - Other topics in areas of applied and interdisciplinary physics.
02.50.-r - Probability theory, stochastic processes, and statistics.
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2001