A dual axis chart allows you to chart different values at different scales.
- Place the column with your values on the Value shelf of your graph.
- Click the down arrow next to the column name.
- Select Axis > Right.
This will change which axis the value is graphed on. Formatting for the left and the right axis are controlled independently of each other. The axes will automatically scale to include the values graphed. You can also manually set the scale for the axes using the Formatting tab.