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: [194.964, 80.506, -41.268, 32.912, -21.6, 21.543, 69.269]
Example Output: 48.047

Example Input: [245.2, 202.565]
Example Output: 223.882

Example Input: [-73.046, -83.771, 1.957, 166.243, 138.615, 162.735, 26.753, 216.297, -95.073, -77.454]
Example Output:
38.326