Level 93

Total Experience Required 5,472,913 [confirmed]

Level 100 progress: 80.18%

This is roughly:
Killing 18,244 people in Warzone, or...
Killing 18,616 people in Execution, or...
Killing 15,461 people in Wingman, or...
Scoring 3,909,224 points in Guardian, or...
Scoring 11,897,637 points in Annex, or...
Scoring 7,201,202 points in Submission.

Horde (TU4)

Completing 27,365 waves on Casual, or...
Completing 18,244 waves on Normal, or...
Completing 13,683 waves on Hardcore, or...
Completing 10,946 waves on Insane.

Or a combination of the above. Have fun!