code: public void setSearchResultsCount(Long searchResultsCount){
          if (searchResultsCount != null && getSearchQuery() == null){
              throw new IllegalStateException("SearchQuery must be set before SearchResultsCount can be set.");
          }
          setParameter(SEARCH_RESULTS_COUNT, searchResultsCount);
      }
docs: We recommend to set the
  search count to the number of search results displayed on the results page.
  When keywords are tracked with {@code Search Results Count=0} they will appear in
  the "No Result Search Keyword" report.  SearchQuery must first be set.
  @param searchResultsCount the search results count to set.  A null value will remove this parameter