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: [58.271, 233.766, -9.758, -40.349, 145.507, 90.294, 186.999]
Example Output: 94.961

Example Input: [82.439, -85.167, 100.665, -83.297]
Example Output: 3.66

Example Input: [-6.757, 191.311]
Example Output:
92.277