There have been times I managed close to 2% on a couple smaller coins - DGB for one, and I think Gridcoin I was pushing close to that before they decided to delist MooWrapper for "not being scientific enough" - while still supporting several other projects that were even less scientific.
To be fair, sometime in the last 6 months they've gotten around to delisting most of those OTHER projects.

At my peak in Folding@Home, I was a bit over 2% - then the "rented farms" fad and a certain developer got crazy-big.

Even some not-entirely-shit coins don't take a lot of horsepower to "go big" on at times.