Santa Clause is being sent more letters this year – and not all of them are from kids. A growing number of parents and grandparents are writing to Santa Clause, according to the United States Postal Service (USPS).

Santa’s helpers, through a USPS program called Operation Santa Claus, receive millions of letters addressed to Santa Claus each Christmas. The helpers read through and try to identify letters from needy children. Those letters are then made Operation-Santaavailable for adoption by individuals or organizations that are willing to provide help to Santa and the kids.

More and more adults are writing and asking for help, according to the USPS, perhaps due to the ongoing troubled economy. Some say they cannot afford the basics, such as winter coats, gloves, hats, or holiday meals. “There’s more than one with the same theme, I’ve never seen anything like it.” said Peter Fontana, who’s been working in the program for 16 years.

Operation Santa Claus was started 99 years ago by then-Postmaster General Frank Hitchcock. The program allowed postal workers and good Samaritans to help Santa out by answering letters and sending gifts to kids who wrote. Fontana said last year was the busiest ever, and that Christmas 2011 is on track to be even bigger.

Operation Santa Claus allows individuals to adopt as many as 10 letters (organizations can adopt more). Identifying information such as the child’s last name, and address are removed from the letter, and it is assigned an identification number. The person who adopts the letter can respond with a letter and a gift, and mail it back to the child using the id number.

About 75 local post offices participate in Operation Santa Clause, a list is available here.