The future price of electricity

I got my electricity bill last week, and I noticed a nifty new feature that's been added to it: a predicted electricity cost for the next year. And very interesting that prediction is, too.

Here is my annual expenditure on electricity for the last few years (the numbers are ridiculously low for several related reasons that I won't go into here):

2003: £45.36
2004: £33.14
2005: £38.26
2006: £51.04
2007: £55.71
2008: £48.74
2009: £48.30
2010: £56.16

The graph shows a noisy but nevertheless upward trend, consistent with inflation more than with any increased usage on my part.

What do you think my electricity company's prediction for my 2011 bill is? A prediction that I am assured is based on "actual readings", according to my account. £60? Maybe as much £70? No. It is £488.77.

So, what does npower know about short term electricity price inflation that I don't?