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: [208.977, 44.479, 123.76, 31.562, 80.258, -34.378, 186.971, 7.439, -99.637]

61.048