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: [201.917, 240.159, 36.615]
Example Output: 159.564

Example Input: [-66.676, -7.063, -18.028, 13.407, 54.369, 148.394, -93.155]
Example Output: 4.464

Example Input: [32.661, 99.26, 20.595, -64.167, 28.87, 196.285, 162.102]
Example Output:
67.944

