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: [80.113, -28.006, -40.254, 222.454, 29.784, 129.871, 141.71, -44.716, -22.74]
Example Output: 52.024

Example Input: [87.258, 29.558, -48.199, -28.615, 46.642]
Example Output: 17.329

Example Input: [167.588, 219.343]
Example Output:
193.466