The chart block now supports multiple Y-axes. Choose which scale to use for each column of numbers by indicating each y-axis in the Y-axes field. Use
y for the left Y-axis and
y1 for the right Y-axis.
In the charts below the data being displayed is the same.
The visual differences are the values for the labels which match the values for the Y-axes, and the font sizes for the legend and x-axis ticks.
Left y-axis only
Note that it may not be immediately obvious to the user which scale applies to which set of data. Hovering over a point, or deselecting a label, may help the user work it out. Alternatively you can publish the raw data for the chart.