How do you pick and choose?

Exam results in the news again - not, as for the last umpteen years, because the percentage of those getting good results has increased, leading to accusations that the exams are getting easier.  No, this time it's the reverse - the percentage of those getting good results has decreased (albeit marginally) and the accusation this time is that this is as a result of deliberate government pressure.  So what, if anything is going on?  Well, there are two ways of awarding grades.  Up to twenty or so years ago, what grade you got depended on how well (or badly) you did in relation to everybody else - so if you were in the top 10% say in a particular subject you might get an "A" - if you were in the next 20%, a "B" and so on.  But then the system changed and you were assessed not against everybody else, but against a set "line in the sand", so it might be for example that if you got 150 marks or better you would get an "A", between 100 and 149 a "B" and so on.  Problem is these "grade boundaries" as they are called are reset every year, and often retrospectively, leading to accusations that they can be, and have been used to achieve a certain result - for political or other reasons.  The current Secretary of State seems to want to go back to the "percentage" method, and certainly I would have thought that this method of ranking you against your peers would be more useful to prospective employers or further education establishments.