I'm not so sure, hc4361, but it may be a matter of semantics.
For example the attached research paper showed that 47% of 16-65 year olds were below Numeracy Level 1. An example of Level 1 would be the ability to work out simple percentages.
http://www.bbc.co.uk/...t_of_low_numeracy.pdf
Okay, 47% is indeed a minority, but I think it is fair to describe it as a 'significant proportion'. When you add in pensioners and teenagers the figure may indeed be nearer 50%.
My experience from teaching is that around half of school leavers and adults cannot work out something such as the price of a £40 item after the price is reduced by 15%. And I reckon nearer three quarters could not work out the original price of an item which is now priced at £44 after a 20% reduction.