A report from a prominent economist finds that the number of permits to carry concealed handguns has skyrocketed by 178 percent in the last eight years, even as the murder rate has dropped.

The figures, cited in a study by the Philadelphia-based Crime Prevention Research Center, is evidence that legally-possessed handguns deter crime, rather than contribute to it, according to the center's president, John Lott, an author and Fox News contributor who has held teaching and research positions at Stanford, University of Pennsylvania, Yale and the University of Chicago. He said the huge increase in the number of permits issued to allow law-abiding Americans to pack heat shows attitudes toward firearms are changing. 

"Americans have increasing come to believe that guns make them safer," Lott said, stressing that African-Americans are increasingly embracing their Second Amendment rights. “A number of surveys show increasing numbers of Americans believe that having more guns owned by their neighbors or in their homes make them safer.”

“More permits means that it is becoming riskier for criminals to attack victims.”

- John Lott, Crime Prevention Research Center

The study’s findings show that 5.2 percent of the total adult population in the U.S. have permits, and that in five states – Alabama, South Dakota, Indiana, Pennsylvania and Tennessee – more than 10 percent of eligible adults may carry concealed handgun permits. In the last year alone, the number of Americans licensed to carry concealed weapons has risen to 12.8 million, a one-year increase of 15.4 percent, according to Lott. 

“More permits means that it is becoming riskier for criminals to attack victims,” Lott said. “The composition of people who are getting permits is also changing. We have seen big increases in both minorities and women getting permits. Having these groups getting permits has a bigger impact on reducing crime.”

While a direct cause and effect cannot be proven, Lott notes that the national murder rate fell to 4.2 people per 100,000 from 5.6 per 100,000 between 2007 and 2014. Overall, violent crime dropped 25 percent in the same period.

Conceal-carry permits for men rose 156 percent and 270 percent for women since 2007, according to the study. The Center also found that minority groups were getting permits at a rate that greatly outstrips that of whites.

“Over the last couple of years, there has been a massive sea change among blacks’ views towards guns,” Lott said, citing a recent Pew Research poll that showed that, over the last two years, African-Americans more than any other group have accepted the notion that owning a gun can prevent them from being a victim of crime.

“The other part of the reason is that states that have had concealed handgun permits for a while have been lowering the cost of getting permits," Lott said, referring to fees and the cost of mandatory training. "As the study notes there is a huge difference across states in the cost of getting a permit. But not too surprisingly, lower costs appear to increase the rate that blacks get permits relative to whites.”

The findings came as Maine becomes the fifth state to pass a law that legalizes either open or concealed carry of a handgun without the requirement of a government permit. Alaska, Arizona, Wyoming, Kansas and Vermont require no permits and more than a dozen states have considered similar legislation, according to Reuters.

While more and more states have been adopting laws to allow individuals to obtain concealed carry permits over the years, gun control advocates say there are more factors involved, and worry about the number of hidden handguns.