Between 2007-08 and 2011-12, the number of firsts awarded by UK universities increased at a faster rate than the overall number of degrees, which rose by 16.8 per cent.
According to the figures, published on 10 January, the number of students gaining 2:1s rose by 20.3 per cent during the period measured, while those gaining 2:2s increased by just 5.4 per cent.
There was little change in the number of thirds awarded or unclassified degrees.
The data show that in 2011-12, full-time students were more likely than their part-time peers to gain the top grade, with 16.2 per cent of the former achieving firsts compared with 12.3 per cent of the latter.
Although women were more likely than men to achieve one of the top two grades in 2011-12, a slightly greater proportion of male students achieved firsts (16.2 per cent compared with 15.4 per cent of female students).