The median income, expressed in Euros per year, represents the value which splits the population in half : 50 % of the population earns either more, or less. It is less sensitive to outlying values (i.e. to a few extremely rich individuals in the population) and is thus more representative of the "average" yearly income.
The Greeks were among the poorest in the Eurozone in 2010 (ranking 13/19), and were even poorer in 2013 (15/19).
A more common indicator, the unemployment rate increased even more dramatically. In Greece between 2010 and 2013, it boomed from 12.7 to 27.5 %.
At the onset of the austerity measures in 2010, Greece had the 3rd largest percentage of people living in extremely precarious conditions.
Three years later, this proportion had increased dramatically, with Greece now ranking 2nd.