Level 75

Total Experience Required 2,634,723

Level 100 progress: 38.6%

This is roughly the same as:

Killing 4,392 people in Warzone, or...
Killing 4,481 people in Execution, or...
Killing 3,722 people in Wingman, or...
Scoring 940,973 points in Guardian, or...
Scoring 2,863,830 points in Annex, or...
Scoring 1,733,371 points in Submission.

Horde (TU4)

Completing 6,587 waves on Casual, or...
Completing 4,392 waves on Normal, or...
Completing 3,294 waves on Hardcore, or...
Completing 2,635 waves on Insane.

Or a combination of the above. Have fun!