====== =======================
        display_range decimals sample
        ============= ======== =======================
        >50           0        ``x = 34.5`` => 35%
        >5            1        ``x = 34.5`` => 34.5%
        >0.5          2        ``x = 34.5`` => 34.50%
        ...           ...      ...
        ============= ======== =======================

        This method will not be very good for tiny axis ranges or
        extremely large ones. It assumes that the values on the chart
        are percentages displayed on a reasonable scale.
        Nr