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.

Example Input: [162.434, 99.656, 86.665, 13.03, 99.225, 43.608, -41.822, 206.671]
Example Output: 83.683

Example Input: [87.234, -30.861, 221.46, 120.15, -85.065, 67.024, 144.174, -64.546]
Example Output: 57.446

Example Input: [210.239, -35.519, 2.9, 217.273, -97.467]
Example Output:
59.485