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: [-67.542, 65.934, 223.305, 25.694, 159.037]
Example Output: 81.286

Example Input: [192.335, 189.22, 235.216, 130.727, 222.285]
Example Output: 193.957

Example Input: [49.831, 245.863, 226.607, 9.173, 181.411, 120.497, 159.845]
Example Output:
141.89