BAD: I don't think we can do this in a way that is useful and honest.
GOOD: The reason that's the case is that we get so few a year that even a single request that we're not legally allowed to reveal the existence of would result in us giving you fundamentally wrong numbers.
TRYING TO SHOW I'M NOT BEING WEASELLY: I'm happy to share right now, because I'm not prohibited from being totally honest: In the last year, including a sealed inquiry - and I'm comfortable acknowledging its existence because it's pretty public - I think we've had exactly 1.
But I don't want to promise we'll keep sharing these, because our low numbers mean that when even one of ours isn't legally sharable, I know we'll be giving you numbers that are insanely off (on a percent basis), and I'd rather be upfront now about our legal limits than be misleading later.
Some thoughts on the companies above:
One semi-related note on DMCA notices As of now, we do publicize DMCA requests - we started uploading them a while back, but had some technical issues with Chilling Effects showing them. You should see any new ones going forward though.
Maybe it would be good to implement a warrant canary.
UPDATE: doesn't look like your request is possible: US spy court says internet firms can't report surveillance requests
UPDATE 2: seems that it has happened at least once (emphasis mine):