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: [110.671, -22.006, 168.421, 152.718, 116.702, -26.669, -55.023, -72.932]
Example Output: 46.485

Example Input: [172.084, 126.948, 90.757]
Example Output: 129.93

Example Input: [40.037, 194.165]
Example Output:
117.101