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: [77.498, 234.955, 184.005, -48.344, 113.167]
Example Output: 112.256

Example Input: [43.554, 122.733, 40.669, 163.641]
Example Output: 92.649

Example Input: [168.038, 68.021, 28.233, -85.98, 20.296]
Example Output:
39.722

