The stats are from StatCounter which has this in their FAQ:

What methodology is used to calculate Statcounter Global Stats? Statcounter is a web analytics service. Our tracking code is installed on more than 1.5 million sites globally. These sites cover various activities and geographic locations. Every month, we record billions of page views to these sites. For each page view, we analyse the browser/operating system/screen resolution used and we establish if the page view is from a mobile device.

So it’s the percentage if web traffic (to sites that use this analytics service)

Safari + AdGuard used to work on my iPad, but it has recently been blocked with a disable Ad-block message. Orion works for me when I disable all build-in content blocking and using the Firefox version of Ublock Origin.

I think the build-in blocker is too basic and gets detected by YouTube, while ublock works (everywhere I’ve tested it, desktop, android, iPad)