Use the following information on states of the economy and stock returns to calculate the standard deviation of returns. (Do not round intermediate calculations. Enter your answer as a percent rounded to 2 decimal places. Omit the "%" sign in your response.)

State of Economy	Probability of State of Economy		Security Return If State Occurs
Recession	.50		10	%
Normal	.45		15
Boom	.05		21

Standard deviation

%