being vacation-phobic

It never came to my mind not to use all the vacation time offered, but I actually know quite a lot of people out there whose vacation days stay unused. Are they vacation-phobic? It turns out that Americans top the ranking lists of this phenomenon. Read more here: http://www.bloomberg.com/news/2014-06-30/vacation-phobic-americans-donate-a-million-years-of-work-annually.html