Since the NSA revelations, many US tech companies have published transparency reports, revealing how often they have been approached by the Govt officials for information. Google, twitter & others have published such reports. Facebook has now joined this bandwagon by publishing the Govt requests for information in the first 6 months of the year. US, India & UK are the top 3 countries for requesting data.
Governments make requests to Facebook and many other companies seeking account information in its official investigations. These usually relate to criminal cases, such as robberies or kidnappings. They may also seek IP address logs or actual account content. This includes both criminal and national security requests.The number of requests from US is between 11K to 12K, India 3,245 & UK at 1,975. Germany, Italy, France & Brazil are some of the other countries in the list.
You will find more statistics at Statista