My older daughter graduated in ‘17 and took 5. My youngest graduates in ‘21 and will have 18.
But her HS is on a binge to team up with a local CC and make many courses “dual enrollment/College in High School” courses. Her 9th grade Pre-Calc class was technically DE as she earned CC credit, as was what used to be just Honors Chemistry in 10th.
12 actual AP courses and 2 “real” DE courses through University of Pittsburgh would be a more accurate.
The school publishes AP awards data and in the past there have typically been 3 or 4 National Scholars, requiring 8 AP tests, and 20-30 “with Distinction”, requiring 5. So the average “top students” probably take 6-7.