Many of the posts here are either highly ranked for certain Google searches or were featured in a major news story, so I’m not surprised they brought in lots of silent readers who never considered making an account. Even the posts that weren’t in those categories were shared widely in the broader EA community, and many of those people also don’t have Forum accounts.
Unique views were pretty close to total views. Here’s a quick screenshot of the two figures for the top ten posts:
I imagine that most repeat views are people reading comments, though it surprises me that the Wikimedia post has the highest fraction of repeat views (since I assume it has many non-EA readers who wouldn’t care much about following the discussion). Maybe a lot of people who get ten Wikipedia ads over the course of a year wound up reading it a few times?