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: [220.545, 177.008, -96.446, 74.375, 87.187, 180.373, 0.673]

91.959