Juan, not a dealer in real property, sold land that he owned. His adjusted basis in the land was $500,000 and it was encumbered by a mortgage for $150,000. The terms of the sale required the buyer to pay Juan $100,000 on the date of the sale. The buyer assumed Juan's mortgage and gave Juan a note for $550,000 (plus interest at the Federal rate) due in the following year. What is the gross profit percentage?