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: [94.752, 94.081, 191.426]
Example Output: 126.753

Example Input: [-12.392, 57.854, 59.291, -18.155, -94.56, 94.214, -38.912]
Example Output: 6.763

Example Input: [3.121, 38.65, 215.525, -51.77, 37.514]
Example Output:
48.608