North Korea’s economic standing is the strongest since Kim assumed power nearly 15 years ago, and likely exceeds any point during the tenure of his father, Kim Jong Il, who ruled from 1994 until his 2011 death, said Stephan Haggard, of the University of California, San Diego, a researcher of North Korea’s economy for decades. “This is an incredible accomplishment for a country that is this poor,” said Haggard, noting that Kim benefited from some luck, too.