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: [79.132, 226.507, 40.498, 100.658, 75.361]
Example Output: 104.431

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

Example Input: [36.003, 222.123, 130.848, 196.514, -41.161]
Example Output:
108.865