Following are three economic states, their likelihoods, and the potential returns:

Economic state	Probability	Return
Fast growth	0.22	15%
Slow growth	0.55	7%
Recession	0.23	-26%

Determine the standard deviation of the expected return. (Note: by convention, the standard deviation is shown in percentage. Do not round intermediate calculations and round your answer to 2 decimal places and do not include a % symbol.)