======= Date Modified 05 Aug 2011 20:22:19 =======
I've seen data somewhere and I'll have a dig around. Might be Times Higher Education Supplement. However, for starters, the last year I saw number expected PhD passes for was 2005.
1) 9640 UK domocile passes;
2) 2065 EU (excluding UK) passes;
3) 4070 passes from student outside the EU;
4) 15780 total passes.
(Source - UK Grad PhD Trends 2007)
If the UK domocile passes are compared to the number of births per year, which stands at 722,000 average between 2001 and 2008 (Wikipedia) then you could argue 1.3% of UK domociles can expect to end up with a PhD.
However, given the birthrate previously was lower, then that value may be a little higher. As people take PhDs at different ages, then this makes the value a little fuzzier again. Also, there will be a little 'natural wastage' before people are old enough and in a position to take a PhD, which may push the figure up towards 2%.
The problem is no proper figure exists estimating PhD holders as percentage of population. Sorry about the rough calculation.