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: [1.435, 246.462, 5.433, -3.093, 31.948, 113.344, 41.816, 43.437, -93.129, 116.292]
Example Output: 50.395

Example Input: [227.404, 94.456, 233.241, 147.762, -31.667, -62.22, -93.912]
Example Output: 73.581

Example Input: [18.274, 29.409, 247.641, 209.428, 135.158, 44.039, 227.479, 117.44, 114.637]
Example Output:
127.056