Over the past decade, unmanned drones have become a prominent feature of contemporary warfare. They allow armed forces to carry out precise and lethal strikes without exposing their soldiers to harm. But they are also becoming increasingly available to non-state actors, such as the Houthi rebels in Yemen, who are backed by Iran. While the United States has long used unmanned aircrafts in that theater of conflict, the Houthi rebels have recently gotten into the drone game too, with striking consequences. Here's a look at the data.