Another North Korean soldier defected at the Demilitarized Zone on Thursday, causing a brief skirmish along the highly fortified border. He was the fourth solder to defect this year, including the one last month who was shot several times by his comrades before he made it to safety in South Korea.

There have been tens of thousands of defections from the communist regime since the 1953 armistice that ended the Korean War. Most don’t occur at the DMZ, a 2.5-mile buffer zone filled with landmines, guard posts and barbed wire.

Here’s a look at some of the demographics of those North Koreans who defected over the years.

This first chart shows the numbers of defectors since 2001, by gender. You can see that women have been more likely to defect — and that there was a sharp drop-off in defections beginning in 2012. That’s the year that Kim Jong Un, the grandson of North Korea’s founder, Kim Il Sung, took power. Coincidence? Probably not.

This next bar chart shows the defector counts by age groups, again while breaking out gender. It’s easier to defect when you’re young, I suppose.

And, finally, a provincial map showing where known defectors came from, with darker shades representing more defections. North Hamgyong Province had the most (more than 18,000), probably because defectors can sneak across the Tumen River — which forms about a third of the border between China and North Korea.