  This paper discusses the empirical evidence of Tsallis statistical functions
in the personal income distribution of Brazil. Yearly samples from 1978 to 2014
were linearized by the q-logarithm and straight lines were fitted to the entire
range of the income data in all samples, producing a two-parameters-only single
function representation of the whole distribution in every year. The results
showed that the time evolution of the parameters is periodic and plotting one
in terms of the other reveals a cycle mostly clockwise. It was also found that
the empirical data oscillate periodically around the fitted straight lines with
the amplitude growing as the income values increase. Since the entire income
data range can be fitted by a single function, this raises questions on
previous results claiming that the income distribution is constituted by a well
defined two-classes-base income structure, since such a division in two very
distinct income classes might not be an intrinsic property of societies, but a
consequence of an a priori fitting-choice procedure that may leave aside
possibly important income dynamics at the intermediate levels.
