Level 38

Total Experience Required 258,416 [confirmed]

Level 100 progress: 3.79%

This is roughly:
Killing 862 people in Warzone, or...
Killing 879 people in Execution, or...
Killing 730 people in Wingman, or...
Scoring 184,583 points in Guardian, or...
Scoring 561,774 points in Annex, or...
Scoring 340,022 points in Submission.

Horde (TU4)

Completing 1,293 waves on Casual, or...
Completing 862 waves on Normal, or...
Completing 647 waves on Hardcore, or...
Completing 517 waves on Insane.

Or a combination of the above. Have fun!