NEST 7: How to get occurrence number for each document?

I'm using NEST 7.0 and C# to run search queries for Elasticsearch storage using Fluent DSL style. I use MultiMatch to search by passed string value in several number of fields:

queryContainer &= Query<Document>.MultiMatch(m => m.Fields(fields)
                                                   .Query(searchParams.SearchValue)
                                                   .Type(TextQueryType.MostFields));

For each document I receive it's _score and Source data. Both I can get from Response.Hits.

BUT how can I get the number of occurrence of the search value for the each document? I'd like to receive something like this:

Search value: "search"
Search fields: title, description
Results:
- Doc1: 5 occurrences
- Doc2: 0 occurrences
- Doc3: 3 occurrences
- Doc4: 1 occurrence
...

Thanks in advance for your help!

There is no direct way to do it in elastic search. The closest thing that can be done is to use multi-term vectors

Query

POST /index51/_mtermvectors
{
    "ids" : ["1", "2"], --> Ids of all documents (_id)
    "parameters": {
        "fields": [
            "text"
        ],
        "term_statistics": true
    }
}

It will return list of all documents with statistics for each word in the field

Result:

{
  "docs" : [
    {
      "_index" : "index51",
      "_type" : "_doc",
      "_id" : "1",
      "_version" : 2,
      "found" : true,
      "took" : 3,
      "term_vectors" : {
        "text" : {
          "field_statistics" : {
            "sum_doc_freq" : 7,
            "doc_count" : 3,
            "sum_ttf" : 7
          },
          "terms" : {
            "another" : {
              "doc_freq" : 2,
              "ttf" : 2,
              "term_freq" : 1,
              "tokens" : [
                {
                  "position" : 0,
                  "start_offset" : 0,
                  "end_offset" : 7
                }
              ]
            },
            "test" : {
              "doc_freq" : 3,
              "ttf" : 3,
              "term_freq" : 1,
              "tokens" : [
                {
                  "position" : 2,
                  "start_offset" : 16,
                  "end_offset" : 20
                }
              ]
            },
            "twitter" : {
              "doc_freq" : 2,
              "ttf" : 2,
              "term_freq" : 1,
              "tokens" : [
                {
                  "position" : 1,
                  "start_offset" : 8,
                  "end_offset" : 15
                }
              ]
            }
          }
        }
      }
    },
    {
      "_index" : "index51",
      "_type" : "_doc",
      "_id" : "2",
      "_version" : 1,
      "found" : true,
      "took" : 2,
      "term_vectors" : {
        "text" : {
          "field_statistics" : {
            "sum_doc_freq" : 7,
            "doc_count" : 3,
            "sum_ttf" : 7
          },
          "terms" : {
            "test" : {
              "doc_freq" : 3,
              "ttf" : 3,
              "term_freq" : 1,
              "tokens" : [
                {
                  "position" : 0,
                  "start_offset" : 0,
                  "end_offset" : 4
                }
              ]
            }
          }
        }
      }
    }
  ]
}

Ids of all documents can be fetched using scroll api