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.

[71.499, 234.969, 205.708, 224.068, 20.084, 217.317, 213.788, 120.222, 134.435, 124.34]
156.643