The recently-released Cisco Visual Networking Index (VNI) Forecast projects that global IP traffic will grow at a combined annual growth (CAGR) of 46% from 2007-2012, nearly doubling every two years. This will result in an annual bandwidth demand on the world's IP networks of approximately 522 exabytes, or more than half a zettabyte, if your vocabulary stretches to that!
Sarita Jones, 22 September 2008