Since The Guardian began leaking top-secret National Security Agency (NSA) documents just 11 days ago, several tech companies responded to the revelations about the PRISM program. The likes of Google, Facebook, and Apple objected to the tone of the press coverage, saying that any suggestion they've ever given a government agency direct access to their servers is false.

Over the weekend, tech companies started responding with additional transparency too. Facebook and Microsoft revealed ranges of how many government information requests they're getting about how many accounts.

Late Sunday, Apple jumped on the transparency bandwagon. The company published a blog post stating that in the past six months, it has received between 4,000 and 5,000 US law enforcement requests for information regarding 9,000 to 10,000 accounts. "The most common form of request comes from police investigating robberies and other crimes, searching for missing children, trying to locate a patient with Alzheimer’s disease, or hoping to prevent a suicide," notes the company.

Every information request is evaluated by the company's legal team and interpreted narrowly, the post states.

Of course, there's a limit to what these transparency disclosures tell us. The tech companies can say no more than the government allows them to say, and no one knows how many of these thousands of information requests were connected to national security or terrorism.

The Apple disclosures include an interesting detail that the other companies do not: a list of several popular products that are spy-proof, because even Apple has no way to decrypt them. Some Apple services—FaceTime and iMessage, in particular—may be mighty useful to anyone not wanting to leave a digital trail for the government:

[C]onversations which take place over iMessage and FaceTime are protected by end-to-end encryption so no one but the sender and receiver can see or read them. Apple cannot decrypt that data. Similarly, we do not store data related to customers’ location, Map searches, or Siri requests in any identifiable form.

Update: A reader points out a recent debate about whether iMessages can be deciphered by law enforcement or not. In April, CNET published a DEA memo suggesting iMessages were untappable, but a counter-theory was put forward that the DEA memo could be wrong, or even deliberate misinformation. "While Apple boasts of 'end-to-end encryption' it's pretty clear that Apple itself holds the key—because if you boot up a brand new iOS device, you automatically get access to your old messages," wrote Techdirt's Mike Masnick. "That means that Apple is storing these messages in the cloud, and it can decrypt them if it needs to."