{
  "fields": [{"type":"int","id":"_id"},{"type":"numeric","id":"Anno"},{"type":"numeric","id":"Estensione rete metropolitana in Km"}],
  "records": [
    [1,2013,64.3],
    [2,2014,65.7],
    [3,2015,72.4],
    [4,2016,72.4],
    [5,2017,73.4],
    [6,2018,72.4]
]}