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.
[232.883, 9.329, 1.211, 202.216, 172.909, 210.917, -70.136, -91.428, 92.194]