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: [75.879, 43.123]
Example Output: 59.501

Example Input: [12.155, 204.528, 85.84, 66.186]
Example Output: 92.177

Example Input: [-14.77, 239.836, 176.436, -95.457, -85.007, 150.576, 110.105]
Example Output:
68.817