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: [-24.069, 49.942, -56.199, 147.337, 81.429, 198.62, -91.886, 33.842, -16.712, -51.661]
Example Output: 27.064

Example Input: [-96.903, -1.489, 182.083, 196.779, -67.602, 202.143, -20.354, -24.817, 194.439]
Example Output: 62.698

Example Input: [177.149, -65.499, -35.027, 40.219, 187.993, 92.916]
Example Output:
66.292