Formatting Dates with YYYY-MM

/* data stolen from https://howmanyleft.co.uk/vehicle/jaguar_'e'_type */

var month_data = [

  {"period": "2012-10", "licensed": 3407, "sorned": 660},

  {"period": "2011-08", "licensed": 3351, "sorned": 629},

  {"period": "2011-03", "licensed": 3269, "sorned": 618},

  {"period": "2010-08", "licensed": 3246, "sorned": 661},

  {"period": "2010-05", "licensed": 3257, "sorned": 667},

  {"period": "2010-03", "licensed": 3248, "sorned": 627},

  {"period": "2010-01", "licensed": 3171, "sorned": 660},

  {"period": "2009-12", "licensed": 3171, "sorned": 676},

  {"period": "2009-10", "licensed": 3201, "sorned": 656},

  {"period": "2009-09", "licensed": 3215, "sorned": 622}

];

Morris.Line({

  element: 'graph',

  data: month_data,

  xkey: 'period',

  ykeys: ['licensed', 'sorned'],

  labels: ['Licensed', 'SORN'],

  smooth: false

});