These numbers are surely numbers on a spreadsheet, unless you are referring to literal bodies that have been counted.

In this article itself, we read that:

> When Estrada-Belli first came to Tikal as a child, the best estimate for the classic-era (AD600-900) population of the surrounding Maya lowlands – encompassing present day southern Mexico, Belize and northern Guatemala – would have been about 2 million people. Today, his team believes that the region was home to up to 16 million

The point is that spreadsheet estimates can be so wrong, they are verging on meaningless.