In this task you will be given a list of numbers and you need to find the mean (average) of that list. The mean of a list can be found by summing every number in the list then dividing the result by the size of that list. The output should be rounded to 3 decimal places.
[107.17, -73.13, -63.072, -44.994, -99.673, -58.318, 143.699, -65.772]