A student's delight as she opens the envelope containing results

Scottish Qualifications Authority figures published on Tuesday showed that 70.8% of Highers were passed in 2006, compared with 71.2% last year.

However, the pass rate for the Standard Grade exam rose from 97.3% to 97.7%.

The SQA said the results showed ongoing strong achievement and blamed pass rate falls on "annual fluctuations".

Pass rates for Higher English, the exam level's most popular subject, dropped two percentage points to 64.1% this year.

However, maths, the second most popular subject, was up nearly one point to 68.6%.

There are always fluctuations with exam results and it is important not to get this out of proportion Education Minister Peter Peacock Tell us about your results

There were mixed results in Scotland's other exams, with pass rates rising and falling respectively for the new Intermediate 1 and 2 tests, which are designed to be half way between Standard Grades and Highers.

Education Minister Peter Peacock congratulated students and defended the Higher exams results.

He said: "We need to have rigorously tested qualifications that maintain our high educational standards.

"There are always fluctuations with exam results and it is important not to get this out of proportion - the SQA advise these results are well within the bounds of what should be expected each year."

A baby boom around 1990 meant more youngsters sat the exams than ever before, with 150,050 candidates compared with 142,799 in 2005.

'Robust system'

SQA chief executive Anton Colella said this meant more students were gaining more qualifications.

"This year's results show continuing strong achievement in a stable system that is maintaining highly regarded standards year on year," he said.

"We are also seeing all the different levels of qualifications being used well - from Access to Advanced Higher."

Scottish National Party MSP Fiona Hyslop said pupils should be congratulated for their efforts and their achievements.

It is essential that people call the helpline as quickly as possible, as colleges and universities make their final selection for courses once the results are out Christina Allon Careers Scotland Director

She added: "We need a robust and rigorous exam system to help power Scotland's worldwide reputation for high quality education."

While also congratulating pupils, Scottish Conservative deputy leader Murdo Fraser said: "It is vital that we have an education system in Scotland which allows every student to make the most of their talents, whether they are academic or vocational.

"That is why Scottish Conservatives have been leading the calls for more vocational training to be introduced in schools in collaboration with our further education colleges."

Careers Scotland has opened its Exam Results Helpline offering advice to students, whatever their grades are.

Director Christina Allon said: "On Exam Results day, students and their families should remain calm and make the most of the impartial advice that is available through the helpline.

"It is essential that people call the helpline as quickly as possible, as colleges and universities make their final selection for courses once the results are out."

The helpline number is 0808 100 8000.