Where and by how much the mail has slowed down in the U.S.

In July and August, when a public outcry rose over late mail, there was indeed slower delivery from the U.S. Postal Service.Since then, on-time delivery of the mail has improved slightly. But for first-class mail — like letters and postcards — the system has remained slower than it was earlier this year.The late-summer slowdown was noticeable on a national scale: to companies that send thousands of pieces of mail daily; to software firms that track that mail; and to the Postal Servic