XYZ Million "in Sales" means...?

[Raymond Chan]

This is a very basic question, but my mom and I are arguing if in sales means price of properties sold combined, or commissions earned combined. I ask this because a very renowned real estate agent (luiz ortiz) retired from real estate recently and had 88 million in sales. But if it was really based on the prices of properties sold combined, then he would have a higher career in "in sales."