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: [191.998, -49.501, -49.007, 115.064, 171.542, -20.141, 30.369, 118.756, 146.515]

72.844