Annual returns of three stocks are given below. Two of them (Air America and Air Brazil) are airline stocks and one (Star Oil) is an oil stock. In general, when oil prices go up, airline company stocks go down and oil company stocks go up.

YEAR	Air America	Air Brazil	Star Oil
2016	-28%	9%	-2%
2017	30%	-28%	-5%
2018	7%	7%	9%
2019	-5%	-2%	-28%
2020	-2%	-5%	30%
2021	9%	30%	7%

How much is the risk (i.e., sample annual standard deviation)? Notice that all three stocks have the same risk. Enter your answer in the following format: 0.1234 Hint: Answer is between 0.1718 and 0.2100