By Angela Harrison
BBC News education reporter
More than 600,000 pupils are receiving results
GCSE grades have reached another record level - with more than one in five exams (21.6%) being awarded an A* or A.
More than half a million teenagers in England, Wales and Northern Ireland have been receiving their results.
Grades have risen almost continually since 1988 and this year more than two in three (67.1%) were between an A* and a C.
Girls continue to get more A*s and As than boys. Fewer teenagers are taking modern languages but sciences are up.
Nearly one in four GCSE entries from girls (24.4%) were awarded an A or A*, compared with 18.7% of those of boys.
This is a slight widening of the gap between girls and boys at the highest grades.
But, if you look at grades A* to C generally, boys slightly narrowed the gap with girls.
Performance by candidates in English GCSES fell slightly at grades A* to C, but for maths it rose - especially among boys.
This improvement by boys is being put down to the end of coursework in the subject.
Languages continued their steady decline, with data from the exam boards showing fewer people taking French (down 6.6% on last year) and German (down 4.2%), but single sciences are gaining in popularity.
Performance across the nations varies, with 66.9% of entries from England achieving A* to C grades and 21.5% getting and A or A*.
In Wales, 65.5% of entries were awarded A* to C and 18.9% were awarded As or A*s.
Northern Ireland's students are still the best performers, with 75.1% of entries gaining A* to C grades and 27.1% gaining As or A*s.
KEY GCSE FACTS 2009
A* to C grades = 67.1% of whole
A and A* grades = 21.6% of whole, up from 20.7% last year
N Ireland A* to C - 75.1%
England A* to C - 66.9%
Wales A* to C - 65.5%
Overall pass rate (A* to G grades) - 98.6%
Schools Minister Vernon Coaker said this year's GCSE results showed sustained progress in standards were the product of hard work.
"I congratulate young people for their achievements today, and we should all take pride in their success.
"The improvements in maths grades are particularly welcome and reflect our sustained focus on getting the basics right. However, it is disappointing to see a slight fall in the English A*-C rate.
"We are not complacent and are targeting our efforts on ensuring that every child performs to their full potential."
General secretary of the National Union of Teachers Christine Blower said the overall picture was one of success.
She added that the reduction in the take-up of modern languages was a "fundamental concern" and that gap in performance between boys and girls needed further investigation.
More than 600,000 students in England, Wales and Northern Ireland are receiving their GCSE results. They were released by the Joint Council for Qualifications, which represents the exam boards.
Results for the first 200 students studying England's new Diploma qualification, designed to mix academic with work-related study, were also released.
On the back of the GCSE results, ministers also expect the number of schools targeted for poor performance to fall to 280, from 631 two years ago.
Schools in England targeted under what is called the "National Challenge" are those where fewer than 30% of pupils achieve five or more good GCSE passes (A* to C) including maths and English.
In January, when the league tables for England based on last year's exam results were published, 440 schools were in this category.
The government says in 1997 the figure was 1,600 - about half of schools - and that now the rate is one in 10.
Those getting their results are among the first to have been educated entirely under a Labour government.
A poll in England for BBC's Newsnight found 67% of those questioned said Labour had not lived up to its education promises.
Students in Scotland received the results of their Standard and Higher grade exams earlier this month.
And many pupils in Northern Ireland had received some of their GCSE results earlier this week because two thirds of exams taken there were set and marked by the local board, the CCEA.
BBC News wants to hear from students receiving their results. What do you plan to do after you get your results? If you fail to make the grade, do you know what you will do next?
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