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: [113.021, 101.946, -14.79, -8.555, -59.095, -74.169, 80.193, 157.87, 26.321, -19.87]

30.287