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: [86.49, 214.099, -90.546, 63.504, 109.644, 231.927, -7.661, -59.778, 17.036, 92.465]

65.718