Half of Americans are in favor of legalizing marijuana, according to a new Gallup Poll indicating record approval for the use of pot, which for now is only legal for medical purposes in 14 states and the District of Colombia.

The survey shows a 4 percent surge since last year, when 46 percent supported the legalization of cannabis nationwide.

The 50 percent in favor of decriminalizing pot is the highest percentage registered since 1969, when Gallup began doing studies on the subject and the approval rating was only 12 percent.

The proportion of U.S. adults who believe that marijuana should continue to be illegal has also dropped since then, now standing at 46 percent compared with 50 percent in 2010.

"If this current trend on legalizing marijuana continues, pressure may build to bring the nation's laws into compliance with the people's wishes," Gallup said in a communique.

The polling company, using results from a survey on crime taken Oct. 6-9, said that the greatest support for legalization comes from self-identified liberals and among people between the ages of 18 and 49.

Though support for decriminalizing use of the drug has been on the rise since the year 2000, initiatives to try and legalize its sale for other than medical purposes have made little progress.

The most notable failure was that of Proposition 19 in California, which tried to decriminalize the growing, sale, ownership and use of cannabis for people 21 and up, which was rejected in a referendum on Nov. 2, 2010 by 56 percent of voters.

Nonetheless, both the use and acceptance of marijuana have continued to increase across the country.

Data from the government's 2009 National Survey on Drug Use and Health indicate that 16.7 million Americans over the age of 12 used marijuana at least once during the month previous to being interviewed.

The study released Monday by Gallup was based on telephone interviews with 1,005 adults nationwide and has a margin of error of plus/minus 4 percentage points.