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.

[6.311, 82.667, -21.764, -1.53, 223.997, 196.953, 189.246]
96.554