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: [-64.231, 200.235, -9.547, -98.817, 222.577, 12.8, 214.705, 122.883, 216.246, 113.126]
Example Output: 92.998

Example Input: [161.683, 162.041, 187.429, -79.681, 60.809, 225.806]
Example Output: 119.681

Example Input: [18.791, 222.774, -4.565, 186.901, 79.113, 0.848, 245.117]
Example Output:
106.997