I am home educating my son, and we have been gradually working up the research for various 'exams'. We've been through the KS2 sats papers online, and most of the KS3 Maths papers, as he is very good at maths.
I have recently started researching GCSE's. It has been very interesting indeed. I discovered a site where a teacher was asking whether to put her pupils in for the Foundation Maths or the Higher Tier. The answer included the information that for Higher Tier, 50% of the questions will be 'low demand', ie aimed at level C to D, 20 to 25% at 'mid demand' ie aimed at level B, and the remaining 25 to 30% at 'high demand', aimed at levels A to A*.
I found another site that told you what percentage you had to get to achieve each grade.
81% or above gets you an A*
59.5% gets you an A (note that to get this you need not actually complete ANY work in the 'high demand' section.
41.5% gets you a B (note also that this falls within the 50% aimed at levels C and D)
23.5% gets you a C (less than a quarter of the paper correct!!!!!!!)
13.5% gets you a D
8.5% gets you an E (maybe marks for writing your name correctly?)
As I have found this same scenario to apply to KS3 and KS2 SATS papers, I would hazard a guess that the rise in the number of pupils with high marks at GCSE and A level is perhaps due to the fact that they can get a mark that indidcates a higher level of achievement than they have actually merited.
This information took quite a lot of digging to find, but I would imagine it applies across most subjects.
In my day (O levels) all the Maths paper was hard.
Look online - lots of old papers are available free. See how hard you find them. I would have no trouble getting an A* after a little revision of the higher grades work, and I only got a Grade 4 at O level (in the days when passes were graded 1 to 6.)
Our kids are NOT getting cleverer, the examiners are.