Declining vacation time from work

Despite available vacation days, it appears that American workers are taking less and less vacation. Andrew Van Dam, for The Washington Post’s Department of Data, has the demographic breakdowns:

It does not seem to be a matter of vacation-day supply. It is true that the United States is the only advanced economy without guaranteed paid vacation. However, BLS data on employee benefits suggests that more than 90 percent of full-time, private-industry workers have access to paid vacation time, a figure that has remained relatively steady for decades. And the number of paid vacation days offered by the typical employer has ticked up in recent years.

So we looked instead at vacation-day demand: Who uses the most? Has that changed?