That chart does not at all show that it follows South Korea! It is massively behind and has suffered a debilitating famine in the 90s. That on top of the spurious data collecting in North Korea that probably skews those numbers.

The people against sanctions want countries around the world to be forced to trade with North Korea. We don't have to be forced to trade with anyone. Free trade is earned, not a right for all the dictators of the world.