The major reason is the growth of electronic financial services and e-mail, the San Francisco Chronicle reported. Postal service spokeswoman Sue Brennan said the volume of mail has dropped by 35 percent in just five years as more people pay bills online.
In 1985, there were about 400,000 blue mail boxes in the country, dropping to 365,000 in 2000. Now, there are about 160,000 left with hundreds being removed every month.
First-class mail began dropping in the 1970s, observers say. Women entered the workforce and had less time to write letters while long-distance telephone calls became cheaper.
Boxes that take in fewer than 25 pieces of mail each day become candidates for removal. Once the decision is made a 30-day notice is posted on the box to give users time to complain to the local postmaster.
"To be honest, we don't get a lot of complaints," James Wigdel, a spokesman for the postal service in San Francisco, told the Chronicle. "The younger generation is moving everything online."