Cell phone service downtime statistics are considered a matter of national security and are not available to the public, not even via FOIA requests.
http://redtape.msnbc.com/2006/12/why_cell_phone_.html
Yup. That’s what makes the service unavailable to John Q. Citizen. During the 2004-05 hurricanes, power, cable and cell service was out for over a week but my land line worked fine.