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: [140.332, 92.06]
Example Output: 116.196

Example Input: [148.261, -51.308, -98.748, -41.832, 44.313, -41.042, -19.943]
Example Output: -8.614

Example Input: [96.921, 188.823, 195.627, -32.429, 144.606, -13.635, -44.458, 48.391, -19.867, 162.804]
Example Output:
72.678