SEE ALSO: As Papers Mull Online Charges, Print Cover Prices Go Up And Up

We sifted through eight years of available cover-price and ABC-circulation data for the weekday editions of The Guardian, The Times, The Daily Telegraph, The Financial Times, The Independent, The Sun, Daily Mirror, Daily Mail, Daily Express, Daily Star...

The average cover price rose 28.2 percent from £0.51 in 2001 to £0.71 for the first seven months of 2009. At the same time, the total annual circulation of the 10 dailies fell 19.11 percent. That’s a perverse correlation, but papers have little choice in the face of falling evaporating custom and falling ad sales.

Consider the advertising revenues newspapers have lost to online competitors, in the middle of a recession no less, and it’s not hard to see why the likes of Rupert Murdoch and John Ridding speak so passionately about the need to charge online readers.

Here’s our Wednesday breakdown of how individual papers have hiked their prices. But cover prices can only go up so far to recoup losses. If publishers are going to continue to employ hundreds of journalists in the next decade, it’s clear that another revenue stream has to emerge from somewhere.