I can't vouch exactly for the 96%. I heard on the radio a few months ago that only 4% of British citizens don't have mobile phones. No matter. The truth is that Celldar is a secret government programme which can monitor every move you make in 'real time' from your mobile phone signal. If you carry a mobile phone then you're already carrying a tracking device.
Read How mobile phones let spies see our every move, an Observer article by Jason Burke and Peter Warren, here. Incidentally, Jason Burke has written what I understand to be an authoritative book about Al Qaeda, called Al Qaeda, covering some of the Al Qaeda myths and lies spun by the government and reported in the media. He was also featured in the excellent BBC documentary The Power of Nightmares. See excerpt below.