Swap X and Y axes on Numbers 3.1

This link is now outdated with the new release of numbers.

I want to transpose the X- and Y-axes on a chart in Numbers 3.1. How the heck can I do this?

The first chart I made was able to sum my columns up to 100 just fine:

However, when I try it with fewer columns/geographies, it transposes the selection:

Even when I transpose the cells, it still forces the data to display incorrectly and there is no option to swap the axes:

I'm so frustrated with this! How can I make it plot correctly? Thanks!

Solution 1:

Was having the same problem – apparently the options to swap axes moved to the bottom left when Editing Data References:

Answer found here.