Brenda and Louise are twin sisters who each married 20 years ago. Brenda and her husband run a small piano tuning business. They have had a small, loyal customer base, and their modest but adequate income has not changed over time. Louise and her husband each work for a corporation, and their incomes have steadily increased over the last 20 years allowing them to increase their standard of living. Assuming that Brenda and Louise began their married lives equally happy, and based on their income histories alone, what would you predict about the subjective well-being of Brenda and Louise today?