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: [37.853, 78.283, 143.128, 82.561, 181.661, -89.154, 50.037]
Example Output: 69.196

Example Input: [-55.198, 36.097, 190.132]
Example Output: 57.01

Example Input: [-1.586, 127.301]
Example Output:
62.858