commit: fb200d8 - #595 (2014-04-14 00:44:57 -0400)
Your search traffic has been mugged by iOS 6. Don't forget to reclaim this stolen search traffic when you're putting together your progress reports.
I've updated this post to reflect that Android 4+ traffic also exhibits the same problem. The difference probably gets you to 5.1% in 78 Minutes. (The Android versioning bit took a bit longer.)
Chrome/Google SSL is also removing referrers.