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: [-8.987, 188.004, 159.267, 3.426, 90.685, 181.514, 214.063, 14.6]

105.321