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: [41.573, 107.077, 26.564, -66.491, -90.163, 199.995, -28.782]
Example Output: 27.11

Example Input: [218.807, 72.849, 7.838, 124.81, 45.929, 239.888]
Example Output: 118.354

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