Level 82

Total Experience Required 3,602,645 [confirmed]

Level 100 progress: 52.78%

This is roughly:
Killing 12,009 people in Warzone, or...
Killing 12,254 people in Execution, or...
Killing 10,177 people in Wingman, or...
Scoring 2,573,318 points in Guardian, or...
Scoring 7,831,837 points in Annex, or...
Scoring 4,740,323 points in Submission.

Horde (TU4)

Completing 18,014 waves on Casual, or...
Completing 12,009 waves on Normal, or...
Completing 9,007 waves on Hardcore, or...
Completing 7,206 waves on Insane.

Or a combination of the above. Have fun!