Yeah, that's probably the main limitation right now. This is measuring /new, so it's every submission rather than just the stuff that makes the front page.

lcamtuf's survey (linked in the footer) was looking at the front page, and the number there was quite a bit higher. So there's likely some effect from voting, although I haven't dug into that yet.

I think Algolia has a way to filter for front-page stories, which should make it pretty easy to add. I haven't tested that yet though but will certainly look into it!