Apple handed information about 4,411 user accounts to U.S. authorities between July and December 2015
Outside the U.S., a notable increase in information requests from China is reported. The country made 32 inquiries in relation to 6,724 accounts. This is a humongous increase compared to just 24 inquiries on 85 accounts over the first half of 2015, which Apple explained with ongoing phishing investigations. The company had to handle a total of 178 worldwide emergency requests for information including the contents of communications and customer records. 108 of them came from U.S. bodies.
Account data requests usually contain information originating from a user's iTunes or iCloud subscriptions, which may include name and address, photos, email, iOS device backups, documents, contacts, calendars and bookmarks. All of that can be of potential use to authorities during investigation.
source: Apple via Apple Insider