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: [58.271, 233.766, -9.758, -40.349, 145.507, 90.294, 186.999]
Example Output: 94.961

Example Input: [43.554, 122.733, 40.669, 163.641]
Example Output: 92.649

Example Input: [-70.772, 6.883, 155.287, 91.501, -24.795, -41.265, -85.621, 14.828, 189.461]
Example Output:
26.167