StringID format_str_y_axis;

	byte colours[GRAPH_MAX_DATASETS];

	OverflowSafeInt64 cost[GRAPH_MAX_DATASETS][GRAPH_NUM_MONTHS]; ///< Stored costs for the last #GRAPH_NUM_MONTHS months

	/**

	 * Get the interval that contains the graph's data. Excluded data is ignored to show smaller values in

	 * better detail when disabling higher ones.

	 * @param num_hori_lines Number of horizontal lines to be drawn.

	 * @return Highest and lowest values of the graph (ignoring disabled data).

	 */

	ValuesInterval GetValuesInterval(int num_hori_lines) const

	{

		ValuesInterval current_interval;

		current_interval.highest = INT64_MIN;

		current_interval.lowest  = INT64_MAX;

		for (int i = 0; i < this->num_dataset; i++) {

			if (HasBit(this->excluded_data, i)) continue;

			for (int j = 0; j < this->num_on_x_axis; j++) {

				OverflowSafeInt64 datapoint = this->cost[i][j];

				if (datapoint != INVALID_DATAPOINT) {

					current_interval.highest = max(current_interval.highest, datapoint);

					current_interval.lowest  = min(current_interval.lowest, datapoint);