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.

Input: Consider Input: [18.155, 114.069, 197.871, -99.696, 201.18]

Output: 86.316

Input: Consider Input: [71.91, 41.513]

Output: 56.712

Input: Consider Input: [-21.184, 213.048, -62.869, 66.984, 41.509, 124.51, -37.612]
Output: 46.341