A study by researchers ath the University of Southern California concludes the amount of data stored in the world by 2007 reached 295 exabytes. This is the equivalent of 1.2 billion average hard disk drives and if printed it could cover the entire area of the US or China in 13 layers of books.
The researchers calculated the figure by estimating the amount of data held on 60 technologies from PCs and and DVDs to paper adverts and books.
"If we were to take all that information and store it in books, we could cover the entire area of the US or China in 13 layers of books," Dr Martin Hilbert of the University of Southern California told the BBC's Science in Action.
Scientists calculated the figure by estimating the amount of data held on 60 analogue and digital technologies during the period from 1986 to 2007. They considered everything from computer hard drives to obsolete floppy discs, and x-ray films to microchips on credit cards.