Level 69

Total Experience Required 1,953,486 [confirmed]

Level 100 progress: 28.62%

This is roughly:
Killing 6,512 people in Warzone, or...
Killing 6,645 people in Execution, or...
Killing 5,519 people in Wingman, or...
Scoring 1,395,348 points in Guardian, or...
Scoring 4,246,709 points in Annex, or...
Scoring 2,570,377 points in Submission.

Horde (TU4)

Completing 9,768 waves on Casual, or...
Completing 6,512 waves on Normal, or...
Completing 4,884 waves on Hardcore, or...
Completing 3,907 waves on Insane.

Or a combination of the above. Have fun!