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: [157.631, 106.369, -25.319, 160.78, -87.597, 222.819, -60.99, 36.758, -3.695]
Example Output: 56.306

Example Input: [184.51, 79.649, 31.606, -65.279, 1.231]
Example Output: 46.343

Example Input: [24.623, 226.798, 94.269, 43.28]
Example Output:
97.242