Level 78

Total Experience Required 3,025,167

Level 100 progress: 44.32%

This is roughly the same as:

Killing 5,042 people in Warzone, or...
Killing 5,145 people in Execution, or...
Killing 4,273 people in Wingman, or...
Scoring 1,080,417 points in Guardian, or...
Scoring 3,288,225 points in Annex, or...
Scoring 1,990,242 points in Submission.

Horde (TU4)

Completing 7,563 waves on Casual, or...
Completing 5,042 waves on Normal, or...
Completing 3,782 waves on Hardcore, or...
Completing 3,026 waves on Insane.

Or a combination of the above. Have fun!