At his next doctor's appointment, the patient asks his doctor about an article he read describing the benefits of more frequent dialysis sessions. Consider the graph, which shows the relationship between the urea clearance per session, the weekly standard urea clearance rate, and the number of dialysis sessions each week.

To maintain a weekly standard urea clearance of $20,$ how would the urea clearance per session change if the patient undergoes dialysis six times a week instead of three times a week?