Level 77

Total Experience Required 2,891,154

Level 100 progress: 42.36%

This is roughly the same as:

Killing 4,819 people in Warzone, or...
Killing 4,917 people in Execution, or...
Killing 4,084 people in Wingman, or...
Scoring 1,032,556 points in Guardian, or...
Scoring 3,142,559 points in Annex, or...
Scoring 1,902,075 points in Submission.

Horde (TU4)

Completing 7,228 waves on Casual, or...
Completing 4,819 waves on Normal, or...
Completing 3,614 waves on Hardcore, or...
Completing 2,892 waves on Insane.

Or a combination of the above. Have fun!