CHARLESTON, S.C. - Ten years after it was created, a little-known law requiring marijuana dealers to pay taxes on pot sales has had little impact, officials say.

State officials say it appears not a single dealer has purchased the required stamps. Instead, the stamps have created a market and a demand among collectors.

Of the 433 pot stamps sold by the state since 1994, the overwhelming majority were bought as novelties, according to the South Carolina Department of Revenue.

The stamps are required for every gram of illegal drugs sold by a dealer in the state. They are similar to the stamps affixed to other vices taxed by the state, such as liquor and cigarettes.

A $3.50 sticker is required for every gram of marijuana, which is the most popular among collectors. The current South Carolina marijuana stamps shows a pot leaf imposed over an image of the state with a circle and red stripe superimposed. It's currently for sale at the Department of Revenue office in Columbia.

For other drugs, the tax requires a $200 sticker for every gram of a controlled substance, such as cocaine, and $2,000 for a 50-unit dose of a controlled substance that's not sold by weight, such as pills. None of those have been bought.

When South Carolina's law was created, no one seriously thought drug dealers would line up to buy the stamps. The stamps were created by legislators seeking more tools to prosecute drug traffickers as tax cheats. A drug dealer who violates the stamp law is subject to a fine of 100 percent of the tax, in addition to possible jail time.

As many as 18 other states have similar laws on the books.

But from the outset, South Carolina's tax stamp law has been of little value to enforcement agents.

Because of constitutional concerns over self-incrimination, people who buy the stamps aren't required to give their names, addresses or any other personal data, leaving no way for the state or law enforcement to track where they go.

Additionally, the state Department of Revenue, which produces and enforces the stamps, has profited little from them. There is no mandate for arresting police agencies to contact the revenue department or to include them in a prosecution. When drug dealer assets are divided after a successful prosecution, most of the money recovered goes first to local, state and federal law enforcement agencies. The revenue department usually is last.

In the 10 years the law has been active, the department has received $115,988 from the stamp program, a fraction of the millions of dollars in drugs seized in the last decade. The money was collected mostly in the rare instance when revenue staffers are called in by local police to perform audits.

"There's really no incentive for local law enforcement officials to refer a case to us," said spokesman Danny Brazell. "We do get a few referrals and that's how we've obtained the little bit of money we've gotten from the illegal drug industry in South Carolina."

University of South Carolina criminologist Geoff Alpert said he wasn't surprised South Carolina's drug stamp law is seldom enforced. He said authorities already have plenty of tools to prosecute drug cases.

"The people who sell a lot of marijuana aren't going to be the ones standing in line paying their taxes," he added.