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.

Example Input: [169.922, 249.47, 142.453, -55.768, 155.357, 6.096, -95.702, 243.569, 31.11, -75.031]
Example Output: 77.148

Example Input: [248.385, -40.468, -97.132]
Example Output: 36.928

Example Input: [3.573, 180.339, 145.997, -59.119, 183.85]
Example Output:
90.928