The A-level pass rate in the UK has risen slightly this year to 96.2% of entries, up 0.2 of a percentage point.
As candidates received their results, there was a slightly bigger rise in the proportion of the 783,878 entries awarded grade A: up 0.4 to 22.8%.
Girls' performances remained ahead of boys', but the gap continued to narrow.
The biggest change in subject popularity was in religious studies, with 16.9% more entries than in 2004, at 16,859 in total.
The collated results were published by the umbrella body for the exam boards in England, Wales and Northern Ireland, the Joint Council for Qualifications.
It said the figures showed "a modest but credible improvement" in achievement.
A-LEVEL PASS RATE: UK
The council's director, Ellie Johnson Searle, said: "Students are again exercising their individual choices in a system that promotes exactly that: individuals choosing to study what they are interested in and what they feel they are good at."
"The rise in entries for religious and political studies [up 9.8%] is significant at a time when Britain increasingly needs young people to understand the complexities of our faith communities and participation in our democratic society."
PASS RATES (A GRADES)
England: 96.2% (22.4%)
Wales: 96.8% (23.7%)
Northern Ireland: 97.5% (31.2%)
The pass rate for girls' entries was 97%, up 0.2, and for boys' 95.4%, up 0.4.
As usual, Northern Ireland entries were the most successful, with 31.2% awarded A grades.
POPULAR A-LEVELS: UK TOP 10
(Subject: % of all entries)
General Studies: 7.6%
Art & design subjects: 5.2%
Business Studies: 3.9%
Also published were the results at AS-level, which since the reforms in 2000 is the halfway stage towards a full A-level and a qualification in its own right.
The pass rate rose from 86.9% to 87.3%, with A grades rising from 17.5% of entries to 17.9%.
But A-levels have been the main focus of debate about whether standards are being maintained, given the continuing rise is success rates - up for the 23rd successive year.
England's Schools Minister, Lord Adonis, has insisted that the progress is real.
Even so, the government is committed to reforms to make it easier for universities and employers to distinguish between the best candidates.
And it faced renewed calls for the overarching diploma system advocated in the Tomlinson report on 14 to 19 education, which it has rejected.
Somewhat confusingly, although candidates get their individual results on Thursday, the national figures relate to exam entries rather than candidates.
Provisional national statistics on how students have performed, such as the proportion getting two or more A-levels and their average points scores, will not be available until October.
The national school and college "league tables" for England, based on the results, are not published until the turn of the year.
GCSE-level results are due to be published next week - on Tuesday for the Northern Ireland exam board, and on Thursday for all the boards.