Salam wa rahmatou Allah
Since you work by group, some students work more than other and some students in the group do not work at all.
It is important to indicate in percentage the amount of work done by each student in the cover page.
For example, if we have five student X1, X2, X3, X4, X5 all of them worked the same amount, so each one has done 20%.
At least percentage will give an idea on work distribution.
Best regards
Dr. Anis