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: [9.625, -27.168, -78.835, 117.698, -73.784, 146.253, -90.405, 134.54, 55.581, 205.402]

39.891