What is the proliferation of IMSI Catchers?

A 2014 discvery by prominent newspaper Aftenposten in Norway's capital, Oslo revealed several fake stations. This image shows the german crypto phone in action (revealing fake stations)

Mind you, this is a small investigation that focused on politically/business sensitive areas of Oslo such as goverment buildings, embassies, high-profile enterprises etc.

The image is from this article http://nottmagazine.com/2015/04/05/a-norwegian-watergate/

As for international statistics, your google is as good as mine.

EDIT: if you're curious about the phone, it has a built in firewall to detect suspicious behaviour http://www.cryptophone.de/