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.

[-28.295, -24.828, -66.96, -12.108, -96.597, 110.99, 172.86, -18.752, 157.717]
21.559

[21.953, -90.519, 92.624, 189.808, 130.57, -33.423, -16.126, 31.61, 119.582]
49.564

[50.544, 107.696, 85.929, 188.054, -28.683, -63.888]

56.609