Definition: 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.
Input: [-33.421, 234.099, -68.856, 228.909, -91.024, -21.115, -35.901, -59.716, 94.192, -68.154]

17.901