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: [198.475, -38.691]
Example Output: 79.892

Example Input: [227.601, -61.961, 78.822, -29.52, 126.039, -44.098, 112.374, -19.23, 69.758]
Example Output: 51.087

Example Input: [80.965, 237.421, 199.121, 135.429, 47.982, 86.347, -57.786, 152.241, -83.536, 6.766]
Example Output:
80.495