# File languages-statistics.rb, line 881
        def depth()
                if @number_of_articles < @@minimum_number_of_articles_for_calculating_depth then
                        return nil
                end
                # (edits / pages) * (((pages - articles) / articles) ** 2)
                return (((number_of_edits.to_f) / (number_of_pages.to_f)) *
                                (((number_of_pages - number_of_articles).to_f / number_of_articles.to_f) ** 2)).to_i
        end