“…4 The Downloaded by [New York University] at 08:25 02 August 2015 primary source for data on unemployment is the Ministry of Employment and Social Security, General Treasury of the Social Security Public State Employment Service, 5 and the data are publicly available. The density of population has been considered, for instance, by Evanoff [10] and, previously, by Lanzillotti and Saving [19] and Seaver and Fraser [23]. This information is provided by the Caja España-Duero, and it is publicly available via its web page.…”