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: [159.965, 172.082]
Example Output: 166.024

Example Input: [-82.094, 163.171, -35.384, 69.572]
Example Output: 28.816

Example Input: [-33.291, 215.237, 130.783, 48.065, 234.926]
Example Output:
119.144