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: [238.315, 168.986, -67.694]
Example Output: 113.202

Example Input: [219.336, -29.108, -41.612, 105.709]
Example Output: 63.581

Example Input: [93.721, 169.755, 236.488, 234.255, 107.15, -63.965, 170.647, 35.878, -34.218]
Example Output:
105.523