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: [109.109, -95.395, 5.04, 45.497, 56.443, -72.916]
Example Output: 7.963

Example Input: [-69.698, 181.415, -43.045, 160.857]
Example Output: 57.382

Example Input: [81.595, 216.575, 226.88, -82.428, 212.015, 6.748, 196.367, -63.121]
Example Output:
99.329