By Yi Whan-woo

The number of North Koreans who defected to South Korea from January to July reached 815, up 15.6 percent from the same period last year, the Ministry of Unification said Tuesday.

The figure was 2,706 in 2011 but dropped to 1,502 in 2012. It bounced back to 1,514 in 2013 but fell to 1,397 in 2014 and down to 1,276 last year.

The official also said such an increase possibly indicates accelerated destabilization of the Kim Jong-un regime.

The Database Center for North Korean Human Rights, a private research institute in Seoul, agreed.

Citing its survey, the institute said there have been an increasing number of elites among the defectors recently.

"A growing number of survey correspondents over the past few years said they were part of the middle- and upper-classes in the North," said Yoo Yeo-sang, the chief director of the institute. "Also, the number of defector cases involving North Korean workers who worked outside their country increased significantly this year."

North Korea is believed to have screened its workers for work abroad, including manual laborers and waitresses, from among middle- and upper-class families. They are generally highly-educated and better off than the majority of the North Koreans.

Yun attributed defections among the workers abroad to growing pressure from the Kim regime to earn hard currency despite the U.N. Security Council's harshest sanctions imposed against Pyongyang in March.

The sanctions are aimed to cut off the flow of cash into the repressive state and prevent it from using the money to continue developing nuclear weapons.