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: [-26.828, 140.474, 94.128, 88.41, 126.87, 175.56, 58.633, 206.244, 100.455, -92.055]

87.189