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: [54.32, -77.717, 25.865, -28.992, -78.908, 135.146, 135.358, 156.696, -92.81, -98.745]

13.021