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: [14.166, 216.734, -23.073, 209.811, 203.336, 91.659, 142.602, 1.151, -39.869, -54.838]

76.168