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: [38.24, 196.576, -84.173, -45.001, 1.607, 170.177, 234.811, -60.183, -91.513]
Example Output: 40.06

Example Input: [149.806, 232.621, 119.06]
Example Output: 167.162

Example Input: [140.17, 70.209, 204.563]
Example Output:
138.314