The Program on Extremism at George Washington University has routinely published statistics indicating that the “vast majority” of individuals charged in the U.S. with offenses related to ISIL are U.S. citizens. When considering all terrorism offenses, that claim holds up—80 of the 97 suspects arrested in the past two years, or more than 82 percent, are American citizens.

Most of those, notably, are not naturalized citizens. Of the U.S. citizens, only six were naturalized. In other words, more than 76 percent of individuals arrested by the FBI over the past two years for terrorism-related offenses were U.S. citizens as a result of having been born in the United States.

Much more at the link with a full breakdown:  

https://lawfareblog.com/its-not-foreigners-who-are-plotting-here-what-data-really-show  

Clawing through the rhetoric when this EO was first signed, I thought it wasn't neccessarily bad (and did not think it was Unconsitutional). The more I read, though, the more I am convinced that this does nothing to solve problems. Not only was it very poorly executed (Ready, Fire, Aim), but it is blind to what the actual problems are. And articles like this further solidifies this line of thinking. It seems to be a huge waste of time, resources, energy and political capital.