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: [32.131, 116.887, 66.741, 218.719, 106.049, -93.999]
Example Output: 74.421

Example Input: [237.861, 119.858, -8.107, -30.075, 180.524]
Example Output: 100.012

Example Input: [-93.372, 58.665, 230.024, 208.635]
Example Output:
100.988