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: [48.122, -2.158, 12.547, -39.257, -62.936, 120.37, 133.697, 68.132, 93.801]
Example Output: 41.369

Example Input: [98.834, 143.231, 35.995, -64.696]
Example Output: 53.341

Example Input: [58.045, -76.66]
Example Output:
-9.307