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: [147.735, -57.013, 16.463, 10.407, 63.145, 3.314, 76.049, 220.801, 100.897]

64.644