Level 36

Total Experience Required 220,039 [confirmed]

Level 100 progress: 3.22%

This is roughly:
Killing 734 people in Warzone, or...
Killing 749 people in Execution, or...
Killing 622 people in Wingman, or...
Scoring 157,171 points in Guardian, or...
Scoring 478,346 points in Annex, or...
Scoring 289,525 points in Submission.

Horde (TU4)

Completing 1,101 waves on Casual, or...
Completing 734 waves on Normal, or...
Completing 551 waves on Hardcore, or...
Completing 441 waves on Insane.

Or a combination of the above. Have fun!