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: [219.769, -36.26, 3.121, -22.5, 124.372]
Example Output: 57.7

Example Input: [49.462, -87.869, 36.985, 94.248, 175.789]
Example Output:
53.723