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: [57.478, 212.225, -90.816, -10.092, 238.514, 60.36, 59.627]
Example Output: 75.328

Example Input: [96.706, 239.918, 73.299, 68.184, 233.512, -76.407]
Example Output: 105.869

Example Input: [241.578, 59.676, 209.038]
Example Output:
170.097