public Number getStartYValue(int series, int item);

    /**
     * Returns the ending Y value for the specified series and item.
     *
     * @param series  the series (zero-based index).
     * @param item  the item within a series (zero-based index).
     *
     * @return The ending Y value for the specified series and item.
     */
    public Number getEndYValue(int series, int item);