Since Anne has brought Susan into the emergency room only two hours after the overdose, you suspect that Susan's stomach might contain undissolved aspirin that is continuing to be absorbed. The fact that Susan is experiencing severe respiratory alkalosis 10 hours after the ingestion confirms your suspicion. When the stomach is at pH = 2.15, what fraction of the acetylsalicylic acid is unprotonated? Express the fraction as a decimal; use 3 decimal places.