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: [41.081, 166.314, -14.556, -84.648, -8.286]
Example Output: 19.981

Example Input: [181.256, -78.191, 162.427, -90.527, 123.709, 248.073]
Example Output: 91.124

Example Input: [-48.602, -1.689, 34.762, 101.381, -25.182, 71.517, -79.039, 39.107]
Example Output:
11.532