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.
[72.369, 166.749, 213.343, 246.021, 190.294, -91.645, -31.149, 157.844]