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: [145.697, -40.957, -46.926, -55.065, 177.211, 204.811, -94.192, -47.466]
Example Output: 30.389

Example Input: [243.697, 165.796, 114.518, 207.298, 191.227]
Example Output: 184.507

Example Input: [-80.516, 10.557, 143.435, -26.467]
Example Output:
11.752