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: [85.354, -22.629, 51.171, 238.376, 177.126, -90.135, -84.086, 175.426, -80.74]
Example Output: 49.985

Example Input: [208.757, -63.857, 124.458, 25.069, -39.093, -85.924, 112.747]
Example Output: 40.308

Example Input: [197.73, 206.105, 102.402, 38.741, 116.866, 78.231, 138.568]
Example Output:
125.52

