A study from Ipsos MORI carried out last year took a look at how public perceptions and actual facts differ wildly. For example;

• We think that 15% of girls under 16 get pregnant every year - official figures suggest it is around 0.6%
• 29% of people think we spend more on Job Seekers Allowance than pensions – actually, we spend £74.2 billion on pensions and £4.9 billion on JSA
• The public (on average) think that £24 of every £100 spent on benefits is claimed fraudulently, when official estimates are £0.70
• 26% think foreign aid is one of the top 203 items government spends money on, when it actually makes up 1.1% of expenditure (£7.9bn.) More say this is the top item of expenditure than pensions.

Somewhat depressing, when you consider that these are the people who elect the politicians they think will address the issues they feel are most important.

Data tables (albeit in a horribly formatted PDF) are also available for download.