Definition: 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.
Input: [-77.909, 106.994, -93.846, 197.9, -15.053, 218.34, -11.104, 99.708]

53.129