The good news is that we used slightly more vacation time in 2015 than we did the year before, according to research released this week by Project: Time Off.

But there’s a problem with that fact, on its own. The State of American Vacation 2016, which is the latest survey released via the U.S. Travel Association initiative, found that between 2014 and 2015, U.S. workers actually gained an extra day of paid time off (PTO) compared to the prior year, amounting to an average of 21.9 days of vacation yearly. The uptick in PTO used (from 16 days to 16.2 days) was so small that, on average, we’re still using less of our PTO than ever.

So what’s causing us to use less vacation? Well, in a word, technology. The study found that economic trends tended not to change the way that we used time off. Instead, the rise of the internet and the mobile phone seem to be the mitigating factors—we’re stuck checking our devices more often, and that leads to more working vacations.

“Rather than tracking broad economic indicators, America’s time off habits closely track trends in technology innovation and adoption,” the report states. “The greater the spread and use of new technologies, the less time off Americans take.”

As a result of this shift, 55 percent left vacation days on the table in 2015, according to the survey of 5,641 full-time U.S. workers.

In comments to the Society for Human Resource Management, Project: Time Off Senior Program Director Katie Denis described the failure to take all of our vacation days as a side effect of our inability to disconnect from the never-ending stream of emails.

“Much of the pressure not to take vacation is self-motivated,” Denis said. “And that’s exacerbated by our connectivity.”

This behavior has an economic effect, as well. If we take less time off, we travel less, and therefore, we spend less. Curious to learn more? Check out the infographic below:

The full study is available on the Project: Time Off website [PDF].

(iStock/Thinkstock)