ES date histogram aggregations query results

gistfile1.txt

{
  "total": 5,
  "dateRange": {
    "from": "2017-05-08T00:00:00Z",
    "to": "2017-05-08T23:59:59Z"
  },
  "aggregations": {
    "views": {
      "buckets": [
        {
          "key_as_string": "2017-05-08T04:00:00.000Z",
          "key": 1494216000000,
          "doc_count": 4
        },
        {
          "key_as_string": "2017-05-08T05:00:00.000Z",
          "key": 1494219600000,
          "doc_count": 0
        },
        {
          "key_as_string": "2017-05-08T06:00:00.000Z",
          "key": 1494223200000,
          "doc_count": 0
        },
        {
          "key_as_string": "2017-05-08T07:00:00.000Z",
          "key": 1494226800000,
          "doc_count": 0
        },
        {
          "key_as_string": "2017-05-08T08:00:00.000Z",
          "key": 1494230400000,
          "doc_count": 0
        },
        {
          "key_as_string": "2017-05-08T09:00:00.000Z",
          "key": 1494234000000,
          "doc_count": 0
        },
        {
          "key_as_string": "2017-05-08T10:00:00.000Z",
          "key": 1494237600000,
          "doc_count": 0
        },
        {
          "key_as_string": "2017-05-08T11:00:00.000Z",
          "key": 1494241200000,
          "doc_count": 0
        },
        {
          "key_as_string": "2017-05-08T12:00:00.000Z",
          "key": 1494244800000,
          "doc_count": 0
        },
        {
          "key_as_string": "2017-05-08T13:00:00.000Z",
          "key": 1494248400000,
          "doc_count": 1
        }
      ]
    }
  }
}