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: [165.647, 110.893, -83.152, -56.699, 19.53, 48.825, -64.043, 199.192, 249.46, 244.789]
Example Output: 83.444

Example Input: [219.428, 229.08, 24.616, -83.165, -28.839, 195.219, 170.491, -78.673]
Example Output: 81.02

Example Input: [186.849, 248.69, -78.191]
Example Output:
119.116