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: [-67.137, 28.093, 232.79, -1.292, 178.555, -80.323, 21.61, 49.346, -66.524]

32.791