The Libertarian candidate Gary Johnson might set a record this year for highest votes attained by a third party candidate.
https://en.wikipedia.org/wiki/United_States_presidential_ele...
It's the young and economically squeezed vote you need to keep track of, both on the right and left. Trump and Sanders both knew this.
As long as the majority of voters think of Trump as a broke racist narcissist and Clinton as an apathetic or unethical elitist he may well have a chance.
http://heatst.com/politics/gary-johnsons-polling-numbers-rea...
But no, the 13% was one poll's result for Johnson's general support, not simply a favorable demographic for him.
I take that pretty seriously.