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.
[226.538, 249.881, 87.913, 108.247, 49.816, 12.151, 150.461]