Apple :
"In 2012, Apple joined the PRISM data collection program run by the National Security Agency (NSA)."
"The firm added that between 1 December 2012 and 31 May 2013 it received between 4,000 and 5,000 requests from US law enforcement for customer data, involving between 9,000 and 10,000 accounts or devices. It did not say with how many it had complied."
just as a point of comparison, google had 25,879 requests involving 42,500 accounts in approximately the same time period (january 1 through june 2013)
google complied with ~65% of the requests
("fun" tidbit: the number for the last half year are 304,915 requests for 748,478 accounts, and google complied with.... 98%!)
Whatever number they give publicly on how many US law enforcement requests they received you can be sure that number won't include anything they turned over the NSA which is probably everything in their cloud all of the time. We know they backdoored the devices (https://www.cultofmac.com/news/nsa-spyware-allegedly-gives-b...)