What has hapened to DRPK's missile tests?

Does this mean Korean tests have suddenly started failing or that someone is taking the missiles out?

This Is The Worst Year For North Korean Missile Test Success In 33 Years

Zero Hedge,

2 May, 2017

As tensions between the United States and North Korea continue to grow, President Trump has warned "major, major conflict" between the two countries is possible. He added that he would prefer to solve the situation through diplomacy before praising Chinese President Xi Jinping, calling him "a very good man" who loves his country. The outbreak of hostilities could prove devastating for the South Korean capital, Seoul, which is targeted by thousands of artillery pieces dug in just over the border.

However, as Statista's Niall McCarthy notes, the pressing issue continues to be the country's ballistic missile program and its efforts to develop a nuclear warhead small enough to fit into a missile capable of striking Japan, the U.S. bases on Guam or the continental U.S. Itself.

Is American concern at developments in North Korea justified?

You will find more statistics at Statista

As can be seen on the following infographic, the pace of missile testing has accelerated steeply, even though many of the launches have resulted in failure. This year alone, Pyongyang has tested 9 ballistic missiles with 5 of the tests resulting in success (including Friday's failure), according to the Nuclear Threat Initiative.

2017's mere 55% success rate is the worst since 1984's 50% success rate.

In 2016, 24 tests were carried out - 14 were successful and 10 resulted in failure