{
    ...
    "aggregations": {
        "errors": {
            "buckets": [
                {
                    "key_as_string": "2015-07-20",
                    "key": 1500501600000,
                    "doc_count": 3
                },
                {
                    "key_as_string": "2015-07-25",
                    "key": 1500933600000,
                    "doc_count": 2
                },
                {
                    "key_as_string": "2015-07-27",
                    "key": 1501106400000,
                    "doc_count": 15
                }
            ]
        }
    }
}