anchor.diff:  
   experimental[]
   
  -The field stats api allows one to find statistical properties of a field without executing a search, but
  -looking up measurements that are natively available in the Lucene index. This can be useful to explore a dataset which
  -you don't know much about. For example, this allows creating a histogram aggregation with meaningful intervals.
  -
  -The field stats api by defaults executes on all indices, but can execute on specific indices too.
  +The field stats api allows one to find statistical properties of a field
  +without executing a search, but looking up measurements that are natively
  +available in the Lucene index. This can be useful to explore a dataset which
  +you don't know much about. For example, this allows creating a histogram
  +aggregation with meaningful intervals based on the min/max range of values.
  +
  +The field stats api by defaults executes on all indices, but can execute on
  +specific indices too.
   
   All indices:
   
  
positive.code: --------------------------------------------------
  
  <1> The `_all` key indicates that it contains the field stats of all indices in the cluster.
  
  With level set to `indices`:
  
  [source,js]
  --------------------------------------------------
  curl -XGET "http://localhost:9200/_field_stats?fields=rating,answer_count,creation_date,display_name&level=indices"
  --------------------------------------------------
  
  [source,js]
  
negative.code: 
  Supported request options:
  
  [horizontal]
  `fields`::  A list of fields to compute stats for.
  `level`::   Defines if field stats should be returned on a per index level or on a
              cluster wide level. Valid values are `indices` and `cluster` (default).
  
  [float]
  === Field statistics
  
  The field stats api is supported on string based, number based and date based fields and can return the following statistics per field:
  
  [horizontal]
  `max_doc`::
  
  The total number of documents.
  
  `doc_count`::
  
  The number of documents that have at least one term for this field, or -1 if
  this measurement isn't available on one or more shards.
  
  `density`::
  
  The percentage of documents that have at least one value for this field. This
  is a derived statistic and is based on the `max_doc` and `doc_count`.
  
  `sum_doc_freq`::
  
  The sum of each term's document frequency in this field, or -1 if this
  measurement isn't available on one or more shards.
  Document frequency is the number of documents containing a particular term.
  
  `sum_total_term_freq`::
  
  The sum of the term frequencies of all terms in this field across all
  documents, or -1 if this measurement isn't available on one or more shards.
  Term frequency is the total number of occurrences of a term in a particular
  document and field.
  
  `min_value`::
  
  The lowest value in the field represented in a displayable form.
  
  `max_value`::
  
  The highest value in the field represented in a displayable form.
  
  NOTE: Documents marked as deleted (but not yet removed by the merge process)
  still affect all the mentioned statistics.
  
  
  .Cluster level field statistics
  ==================================================
  
  [source,js]
  --------------------------------------------------
  GET /_field_stats?fields=rating,answer_count,creation_date,display_name
  --------------------------------------------------
  
  [source,json]
  --------------------------------------------------
  {
     "_shards": {
  