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: [-74.732, 85.225, 17.913, -35.834, 12.561, -23.102, 167.348, 199.993, 168.679, 231.692]

74.974