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: [-71.745, -18.239, 214.837, -22.915, 180.841, -4.641]
Example Output: 46.356

Example Input: [116.268, 173.27, 228.827, 52.695, 66.445, -34.051, 152.137]
Example Output: 107.942

Example Input: [105.656, 162.482, 9.618, 180.797, 27.572, 157.868, 224.435]
Example Output:
124.061