Oxford's own website shows their claimed employment statistics for the last few years as follows:-
2006 : 170
2007 : 249
2008 : 199
2009 : 112
2010 : 158
giving a total of 888 graduates gaining employment over the last 5 years.
Since OAA churn out around 300 integrated grads per year and another 50 modular grads per year, that would make a total of around 1,750 grads over 5 years without including students who only completed ground school or MCC/JOC at OAA. I really don't know if the ground school/MCC/JOC students are included in any statistics although they may well be used to boost the figures in lean years. Anyhow just looking at 888 grads getting jobs out of 1,750 grads over 5 years equates to a 50% success rate and not the high 80s% referred to above!
In addition these figures on the OAA website show that last year of the 158 who gained employment, 77 went to Ryanair and 56 went to easyJet where they are actually self employed on a contract basis, normally a 6 month or 1 year contract, and each has had to pay circa 30k pounds/euros for their type training.
I think this shows that the employment hype is just simply hype designed to get prospective students to part with their money when they realistically have at best a 50% chance of getting a flying job.