For years, North-to-South defections amounted to just a trickle. Most of those coming out were men in their 30s and 40s, who held positions that made fleeing relatively easy. Generally, they escaped without help.

Just 41 defectors sought asylum in South Korea in 1995, but nearly every year since then the number has risen. As the number has increased, the typical sex and age of defectors have also changed. There are more women and more families, according to Chun Sung-ho, an official at South Korea’s Ministry of Unification.

“It is possible to get people out, but you cannot say it is easy,” said Lee Jeong-yeon, a former North Korean military officer who defected in 1999.

Lee said he worked for three years along the Chinese-North Korean border, where he supervised agents who pretended to be brokers and guides.

Human Rights Watch reported this year that the North Korean Government, reacting to the increasing number of defections, has stiffened penalties for citizens it catches trying to flee. Under North Korean law, attempting to leave the country illegally is still classified as treason.

Until 2004, the Government imposed relatively light punishment on non-elite citizens attempting to get out. But since then, North Korea has imposed sentences of up to five years in prison, dire punishment indeed.

In recent months, North Korea has beefed up electronic surveillance along the border, strung more barbed wire and erected barriers. Last year, China also increased border security.

Once in China, defectors still face danger, particularly on the low-budget route. Those trying to reach haven in South Korean diplomatic facilities in China are on their own for the last few yards, scrambling to run past Chinese policemen and climb walls. Not all of them make it.