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: [94.752, 94.081, 191.426]
Example Output: 126.753

Example Input: [66.037, 30.958, 124.853]
Example Output: 73.949

Example Input: [56.243, 63.036, 164.806, -60.897]
Example Output:
55.797