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: [194.026, 179.483, 77.885, 111.339, 234.419, 138.685]
Example Output: 155.973

Example Input: [-41.362, 123.84, 236.661, -43.042, 53.399, 15.001, 10.159, 38.886, 74.298, 167.559]
Example Output: 63.54

Example Input: [116.907, 47.0, -76.086, 26.174]
Example Output:
28.499