Scientists have estimated that in 2007, 295 exabytes of data was being stored around the world.

An exabyte equates to a billion gigbytes and the total data stored in 2007 (although this has since increased) is the equivalent of 1.2 billion 'average' hard drives.

Scientists reached the figure by estimating how much data has been stored on some 60 different technologies including CDs, DVDs and even books and adverts in newspapers and magazines from 1986 to 2007.

"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.

Alternatively, if the information was stored on CDs, the stack of discs would reach past the moon.

The research also revealed that in 2000, three quarters of information was stored in an analogue format, but by 2007 just six percent was stored using analogue technologies. Furthermore, two zettabytes of data or 2,000 exabytes of data are broadcast every day, which equates to 172 newspapers per person per day.

Hilbert said the period between 1986 and 2007 was the "information revolution".

"There have been other revolutions before," said Hilbert.

"The car changed society completely, or electricity. Every 40, 50 or 60 years something grows faster than anything else, and right now it's information."

See also: A history of removable storage