Report Document Inspection Rate across reviews

In a review detail report, you can see a document inspection rate (pages/hour) tabulated.

In reports, this does not appear in the available columns.

So, I'm trying to generate this myself using PowerBI.

In the review_metrics_summary, I can see kloc_per_hour but no pages_per_hour.

I've looked through the other table headings and am struggling to see how to calculate this myself. There is no pages total for a review, for example.

How is pages/hour calculated in the detail report?

Thanks in advance.