⁶The data from Ecuador is available at http://www.ecuadorencifras.gob.ec/banco-de-informacion/. Moreover, we assume that the geographical extension of the FUAs identified through the period 2014-2010 are the same and fixed over time, because there is not information of the historical boundaries of the parishes over the time. The OECD database is available at http://www.oecd.org/cfe/regional-policy/functionalurbanareasbycountry.htm.