Level 80

Total Experience Required 3,305,374 [confirmed]

Level 100 progress: 48.42%

This is roughly:
Killing 11,018 people in Warzone, or...
Killing 11,243 people in Execution, or...
Killing 9,338 people in Wingman, or...
Scoring 2,360,982 points in Guardian, or...
Scoring 7,185,596 points in Annex, or...
Scoring 4,349,177 points in Submission.

Horde (TU4)

Completing 16,527 waves on Casual, or...
Completing 11,018 waves on Normal, or...
Completing 8,264 waves on Hardcore, or...
Completing 6,611 waves on Insane.

Or a combination of the above. Have fun!