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: [97.151, 211.662, 13.529, -83.075, 185.97, 7.1, 99.109, -81.725, 17.327]

51.894