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: [166.436, -30.281, 130.558, 146.677, 54.148, 115.868, 18.961, 219.443, 5.878, -82.861]

74.483