An economist wants to know whether these two variables (the help wanted index and the unemployment rate among insured workers) are related. So he acquired the data for these two variables for each month between 1951 and 2010.The economist determined the covariance to be -2.67. The help wanted index had a standard deviation of 5.54. The unemployment rate among insured workers had a standard deviation of 7.05. Find the coefficient of correlation. Round the answer to two decimal places.