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: [228.031, -85.617, 36.164]
Example Output: 59.526

Example Input: [-61.905, -98.66, 90.472, 237.317, 5.243, 196.933]
Example Output: 61.567

Example Input: [249.14, 22.177]
Example Output:
135.658