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: [160.713, 125.985, 186.982, -94.178, 183.77]
Example Output: 112.654

Example Input: [98.834, 143.231, 35.995, -64.696]
Example Output: 53.341

Example Input: [138.493, 120.089, -77.302, -6.35, 147.393, 174.535, 54.408, -43.141]
Example Output:
63.516

