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: [135.807, 205.755, 191.805]
Example Output: 177.789

Example Input: [126.198, -70.303]
Example Output: 27.947

Example Input: [159.792, -43.736, 228.998, -37.566, 168.36, 152.919, -12.736, 235.284]
Example Output:
106.414