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: [60.02, -66.628, -95.571, 114.26, 109.577, 141.08, 154.303, 228.454, 46.856, 7.365]
Example Output: 69.972

Example Input: [125.67, 5.514, 161.93, 107.05, 118.949, 233.815, 230.211]
Example Output: 140.448

Example Input: [-96.833, -66.591, 16.497, 117.61, 155.714, -18.361, 51.448, -26.681, 145.481, -10.042]
Example Output:
26.824