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: [-51.709, 7.971, 56.819, 147.653, 82.016, 33.283, 17.84, -45.317, 152.854, 6.908]
Example Output: 40.832

Example Input: [162.434, 99.656, 86.665, 13.03, 99.225, 43.608, -41.822, 206.671]
Example Output: 83.683

Example Input: [34.842, 115.829, 62.148, 202.664, -84.382, 72.455, -0.305, -1.396, 112.898, 191.272]
Example Output:
70.602