The average size of a sale in the Royal Palm submarket of Boca Raton surged as sales fell short of year-ago levels. The average square footage of a transaction in the final quarter of 2018 was 6,689 square feet, up 40.9% from the year-ago level to the highest average tracked in nineteen years. This shift was consistent with the increase in waterfront sales, which are generally the largest sized homes in this submarket…