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.
[128.385, -84.329, 241.852, 245.243, 212.529, 192.414, 180.395, 45.773]