yLabel =
        this.row.rootViewState.referenceDisplayLabel;
      if (referenceDisplayLabel === this.displayLabel_) {
        referenceDisplayLabel = undefined;
      }
      const displayStatisticName = this.row.rootViewState.displayStatisticName;
      const data = [];
      let unit;

      for (const subRow of this.row.subRows) {
        const subHist = subRow.columns.get(this.displayLabel_);
        if (!(subHist instanceof tr.v.Histogram)) continue;

        if (unit === undefined) {
          unit