Super hard to say, so ... 80th or 90th? With very low confidence.

But I do have very high confidence that the 99th percentile is much larger than petabytes (think: what's next after "exa"), and I believe that many companies these days crack into "peta" territory.

But as I saw another comment mention, I think another, probably more important, consideration besides size in bytes is cardinality and structure. So maybe this whole classification we're doing is kind of beside the point :)