Hard to believe: evolution of income at the top

I am trying to write an article summarising the recent evolution of income inequality in Latin America.  The reduction in all countries but Honduras is well known, but some numbers are just hard to believe.  This is the reduction experienced by top incomes during the period 2001-2012.  The share decreased in almost all countries and in several by more than 20%.  This is hard to reconcile with the evolution of political economy and also with the limited data we have based on tax receipts.

Percentage change in the income share of the top decile, 2001-2012

Source: own calculations with data from SCEDLAS