TUCSON, Ariz. — Erin Santiago of Northridge, Calif., received a wedding invitation in the mail last month.

It was the same day that she received credit card applications from American Express and Discover Card. And nine other pieces of unwanted mail from companies across the city as well as the nation.

Throughout the week, the unsolicited mail kept coming in — by her count, she received 47 pieces of unwanted mail while only eight were wanted. Most ended up in the trash can.

"Some days we don't even get one thing that we want," said Santiago, a mother of a 3-year-old girl and an expected son in October.

On April 21, that was the case as she received her second Discover Card advertisement in seven days as well as three other pieces of junk.

For Adam Clotfelter of Colorado Springs, Colo., his mailbox was filled with 18 unsolicited pieces while his family of four also received 10 wanted mailings during the same week.

Devon Stein of Winchester, Va., received 13 pieces of solicited mail along with seven unwanted pieces. She said the amount of unsolicited mail is usually much higher.

"It figures, because most weeks we will have at least one credit card application per day, and most times they'll include two — one in my name and one in (my husband) Adam's," Stein said. "You would think since we share an address and a last name that they would realize."

Her biggest offender is American Express, which sent her and her husband two identical things on the same day.

"We usually get a lot of crap from them, a lot of times using our Costco membership info, since they're affiliated," Stein said. "We have not once expressed interest in getting an AmEx and we never will."

Junk Mail Stats • Between 40 and 167 pounds of junk mail are sent to every adult each year, with approximately 44 percent going to a landfill unopened. The response rate is less than 2 percent. • The average person gets only 1.5 personal letters each week, compared to 10.8 pieces of junk mail. In a year, an average adult will receive 560 pieces of unsolisited mail. • The production and disposal of junk mail consumes more energy than 2.8 million cars. It also wastes 28 billion gallons of water for paper processing each year. — According to the Global Junk Mail Crisis

According to the Environmental Protection Agency, 100 million trees are used to produce the 4 million tons of junk mail Americans receive each year.

Now, Congress is taking notice of this annoyance and looking into creating a national do-not-mail list, similar to the do-not-call list that prevents telemarketers from calling individuals on the list.

Direct Mail already runs a similar do-not-mail list that thousands have subscribed to.

"As direct marketers ourselves, we know that mail-order companies don't want to waste their money sending mail to people who don't want to receive it. They'll gladly take you off their lists when they're asked to," the Web site says.

According to the Global Junk Mail Crisis, a unsolicited mail stopping service, "If you cut your bulk mail for 5 years, you’ll conserve 1.7 trees, 700 gallons of water and prevent 460 pounds of carbon dioxide from being released into the air."

But do-not-mail lists are not the only way to stop junk mail. Here are three companies to contact if you want to reduce the unwanted mail that comes into your box:

• Consumer Credit Reporting Industry
Endorsed by the U.S. Federal Trade Commission, the Consumer Credit Reporting Industry's OptOutPrescreen.com will help stop credit card mailings for five years or forever.

"If you choose to Opt-Out, you will no longer be included in firm offer lists provided by these four consumer credit reporting companies," the site says. "If you are not receiving firm offers because you have previously completed a request to Opt-Out, you can request to Opt-In."

• Direct Marketing Association
The New York-based organization will help you put a stop to junk mail like catalogs for free if you sign up online or if you prefer, you can mail in registration form along with a $1 check to cover processing.

"Please note that signing up with MPS may prevent you from receiving mail you want, such as new catalogs, coupons, announcements about new businesses in your community, and notices of special offers," the site says.

• GreenDimes
While some companies will charge you to help, GreenDimes is currently paying $1 to anyone who signs up for their basic level service — or if you prefer, your dollar can be donated toward planting a tree.

"GreenDimes employs teams of people whose job it is to contact individual junk mail lists and get you off! We use every means at our disposal, including phone calls, emails and Web forms," the site says. "We'll do whatever it takes to be successful for you."