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: [41.573, 107.077, 26.564, -66.491, -90.163, 199.995, -28.782]
Example Output: 27.11

Example Input: [-61.563, 49.659, 125.562, 130.542, 75.232, 197.442, 175.182, 54.736, 210.833, 65.27]
Example Output: 102.289

Example Input: [136.903, 55.906, 61.519, 224.5, 94.211, 148.896, 90.372]
Example Output:
116.044