A-level students have been awarded the highest proportion of As and A*s since 2012, amid changes toughening the exams in England.
Some 26.4% of exams have been awarded these top grades this year - but the proportion gaining A* to C dropped to 78.4% from 79% last year.
England's exams regulator has said the results show a steady national picture at a time of significant change.
Pupils in England, Wales and Northern Ireland are finding out their results.
Overall, 97.6% of A-level entries were awarded A* to E grades.