I've been re-listening to World War Z as part of my "listen to audiobooks while watching sports" thing I mentioned earlier. I was thinking I wanted to see how far along I was because I keep track of that with my other books using Goodreads, why not audio. But I realized there isn't an easy way to do that. At least not a way that doesn't require me to do math. So, as is the current custom, I complained to Goodreads on Twitter, not really thinking they'd say anything. But they did. The first response involved math
We're not done yet, though, because there's also a matter of getting audiobooks off sites like Audible. I haven't done this (yet!) so I'm not even sure what those are like. Maybe they already track percentage for you and it's an easy addition. Maybe they have the same track list but no discs, so it's just a matter of repeating the same values that are capture for the discs.