As part of a clinical trial, the drug tofacitinib citrate was administered in 5-mg doses to 1336 subjects as a rheumatoid arthritis treatment. Here are the numbers of adverse reactions: 57 subjects had headaches, 21 had hypertension, 60 had upper respiratory tract infections, 51 had nasopharyngitis, and 53 had diarrhea. Construct a frequency table, and include a column for relative frequencies given as percentages. Which side effect was the most common?