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.

[174.098, 19.358, -71.29, 39.0, 202.134, 107.618, 197.578, 14.008, 211.584, -24.934]
86.915