Even Santa would find it a challenge to deliver all the mail and packages handled by the U.S. Postal Service at Christmastime.“On average we will process about a 1,000 packages a day,” said McMinnville postmaster Brent Nunley. “During the Christmas season that will increase to about 4,000 a day. It’s quite an increase.”Nunley said the Christmas rush in McMinnville reflects a nationwide increase in volume that is almost mind boggling.