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.
[-88.262, -7.13, 233.712, -35.159, 235.658, 222.687, 24.571]