A pharmaceutical company is testing the effectiveness of a new drug for asthma patients. The drug is given to 100 volunteers who suffer from asthma, while a placebo is given to 100 other volunteers who also suffer from asthma. After 4 weeks, the volunteers are asked if they noticed improvement in their asthma symptoms. The results of the survey are shown in the contingency table below. What is the probability that a volunteer received the placebo given that he did not report a noticeable improvement in symptoms?

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