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: [77.999, -51.028, 55.312, 144.582, 192.078, -3.162, 49.859]

66.52