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: [186.101, -86.947, 34.364, 216.489, 42.938, 178.119, -91.099, 139.8, 134.67, -24.047]

73.039