Level 68

Total Experience Required 1,853,708

Level 100 progress: 27.16%

This is roughly the same as:

Killing 6,180 people in Warzone, or...
Killing 6,306 people in Execution, or...
Killing 5,237 people in Wingman, or...
Scoring 1,324,078 points in Guardian, or...
Scoring 4,029,800 points in Annex, or...
Scoring 2,439,090 points in Submission.

Horde (TU4)

Completing 9,269 waves on Casual, or...
Completing 6,180 waves on Normal, or...
Completing 4,635 waves on Hardcore, or...
Completing 3,708 waves on Insane.

Or a combination of the above. Have fun!