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: [12.155, 204.528, 85.84, 66.186]
Example Output: 92.177

Example Input: [222.94, 54.014, 232.208, -16.089, 214.915, 2.232]
Example Output:
118.37