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: [106.529, 165.669, 209.569, 197.265, 28.654, 219.457, -65.346, 20.541, 139.632]

113.552