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: [-95.352, -26.358, 34.234, 162.959, 239.101, 137.014]
Example Output: 75.266

Example Input: [-1.833, 218.553, -61.132, -19.027, 87.034]
Example Output: 44.719

Example Input: [166.467, 133.884, 188.261, 235.204, -77.596, -56.129]
Example Output:
98.348