Does Apple keep track of iOS app opening? We would like to know if Apple keeps track of iOS App opening by users.

For example, Facebook keeps track of Facebook app opening to collect data of Facebook Insight.

Does Apple keep track of user behaviours like iOS app opening by users? Thanks.
I just tested this using Apple’s built-in “Music” app on an iPhone 4 running iOS 5.1, using ngrep and tcpdump to monitor network activity. No connections to Apple servers are being made when opening an app on any iOS device.

As you mentioned, individual apps (e.g. Facebook) may keep track of data like this by pinging a server every time you open their app — but Apple does not do anything like this globally.