Using a two-sided graph solves this dilemma by displaying the two series in relation to two different vertical scales, one on each side of the graph.

Combo Charts: Combines two or more chart types to make complex data easier to understand. Useful when dealing with different units of measurement or scale. Practice and Feedback ...

You can combine two columns in Excel using several formulas and tools available in the software. Here's how to combine two columns in Excel.