A couple of points to note that have not already been mentioned:
Pass rates are not the same as success rates. Although the pass rate may be 97%, the figure for people who stick the course and take the exam is much lower. Students who are not likely to pass their exams are encouraged to leave / not allowed on to the A2 course. This filtering process simply didn't happen when I did my 'A' levels in the early 90s.
Furthermore, teachers are placed under even more scrutiny in their teaching and pass rates than when I started teaching in the late 90s. Back then, if I had a bad year, I didn't have to justify myself in the same way that I do these days. Nowadays I have to account for every person who quits / fails on my course.
Also, we're increasingly seeing students coming through to us (at 'A' level) who are pre selected for the courses they are going to do. For example, many students who are not predicted to get a C at GCSE in English Literature, now do Media studies instead, geography students doing travel and tourism and this year I'm seeing loads of students doing these 'equivalent to GCSE' courses instead. Simply, if the schools do not think the students will not get a C, they don't bother allowing them to do that subject.
There are lots of different factors like these which affect the results that students get, and perhaps artifically boost the pass grade that were not employed when I did my GCSEs / A levels in the early 1990s.