Recruiter, hiring managers, etc, how many people would you say completely fail during the first round?

I had an internship interview and it went very well I feel like. We started talking about embedded systems, and my interests in tech overall, which didn't really relate to the job description. The interviewers brought it up for a brief minute due to collateral from a project I have on my resume. We talked about my freelance experience as well. It's a long story, but the entire interview just felt like a conversation that slowly dove more technical the longer it went.

Anyways, I was just wondering about how many interviews do not go like this in your experience? Basically someone walks in or hops on the call for their interview and they pretty much have nothing to show or talk about other than "yea, in whatever class, we had an assignment that was pretty cool, I don't remember much about it but I remember it was fun! Blah Blah Blah." Maybe not that extreme, but still. So, just out of the typical batch for a intern or entry level role, about how many are like this?

Again I feel really really confident about my interview. I know there can always be someone better, or who they think is a better fit. However, they are searching for several interns to bring on for a 4 month interview process basically. The top two will receive full time offers. During the interview they were telling me all about what I would be doing and everything, they discussed the technology they use that sort of relates to my biggest project (which is a game engine, but not specific to the role). So I just feel confident is all, but not excited with my hopes up. So, that is really why I was just curious as to how many people are typically flunks for a lack of a better term.