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: [-46.14, -0.077, 72.663, 81.035, -24.144, 66.514, 98.199]
Example Output: 35.436

Example Input: [-49.786, 238.124, -20.697, 32.014]
Example Output: 49.914

Example Input: [63.559, 115.27, 50.132, 126.874, 241.377, 249.212]
Example Output:
141.071