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: [204.634, 176.221, 167.577, 217.281, 38.905, -60.3, -17.617, -69.258, -5.581]

72.429