Level 16

Total Experience Required 31,436

Level 100 progress: 0.46%

This is roughly the same as:

Killing 53 people in Warzone, or...
Killing 54 people in Execution, or...
Killing 45 people in Wingman, or...
Scoring 11,228 points in Guardian, or...
Scoring 34,170 points in Annex, or...
Scoring 20,682 points in Submission.

Horde (TU4)

Completing 79 waves on Casual, or...
Completing 53 waves on Normal, or...
Completing 40 waves on Hardcore, or...
Completing 32 waves on Insane.

Or a combination of the above. Have fun!