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: [-9.301, -10.629, 88.777, 68.965]
Example Output: 34.453

Example Input: [234.272, 196.413, -92.425]
Example Output: 112.753

Example Input: [70.862, 193.626, 106.469, 38.408, 176.582, 111.828, 189.262, 52.899, 68.363, 212.746]
Example Output:
122.104