Return the number of rows preceding the data table for *series* in
        the Excel worksheet.

def series_table_row_offset(self, series):
        """
        Return the number of rows preceding the data table for *series* in
        the Excel worksheet.
        """
        title_and_spacer_rows = series.index * 2
        data_point_rows = series.data_point_offset
        return title_and_spacer_rows + data_point_rows