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: [14.166, 216.734, -23.073, 209.811, 203.336, 91.659, 142.602, 1.151, -39.869, -54.838]
Example Output: 76.168

Example Input: [89.226, 241.396, 7.011, 114.867, 113.075, 103.559, 83.142, 188.743, -27.33, 180.773]
Example Output: 109.446

Example Input: [220.164, 60.961, -58.509, -16.616, -56.046, 167.183, 82.436, 61.171, 34.153, -6.002]
Example Output:
48.89