In Professor Zarin class, the grades on a group project were as follows: 100,69, 89, 99, 87, 78, 90, 91, 88,...

In Professor Zarin class, the grades on a group project were as follows: 100,69, 89, 99, 87, 78, 90, 91, 88, 72, 80, 79, What is the mean of the grades?