|Level||Total active||MUST||SHOULD||SUGGESTED||Allow N/A||Require URL||Includes details||New at this level||Future|
The "active" criteria are criteria that are included in the percentage calculations (as opposed to "future" criteria). The next columns identify the number of active criteria in each level that are MUST, SHOULD, SUGGESTED, allow a "N/A" as an answer, require a URL, include details, or are new at this level. "Future" criteria are shown on the form, and are expected to be added as active criteria to some level in the future, but are not included in completion calculations.
You can see statistics about projects over time at the project stats page.