Hmm. Looks like ReSharper is doing the right thing (at least in 9.1). I've just verified that installing an extension sends the "NuGet-Operation: Install" header, updating sends "NuGet-Operation: Update". (It doesn't send anything for uninstall, as it doesn't know the original source to tell.) These headers are what's used to update the stats. And we can see that it's working with 1.0.0.53, which has 77 "Install" operations from ReSharper 102.0 (which is 9.1 - no, I've no idea what the 102 means…) But I don't know what's happening with this latest version.
Are you using 9.1 to test with? Can you run it with Fiddler to see what HTTP headers are being sent when you try to download the package? (You'll need to delete it from %LOCALAPPDATA%\NuGet\Cache first)
Slava, do you have any ideas? Any idea why the client is listed as "ReSharper"? That's not what we send as the user agent...
Matt