This is the holiday season, when adults across the U.S. travel far and wide to visit their parents. But for many, the visits will only require getting out of bed.

The number of young adults—specifically, members of the millennial generation—who are living with their parents is on the rise, according to multiple reports.

As of 2016, 15 percent of millennials between the ages of 25 and 35 were living with their parents. That compares to 10 percent of Gen Xers when they were at the same age in 2000, 11 percent of late baby boomers in 1990, 8 percent of early boomers in 1981 and 8 percent of the Silent Generation in 1964, according to Pew Research Center analysis of Census Bureau data.

"Today’s young adults are ... more likely to be at home for an extended stay compared with previous generations of young adults who resided with their parents," Pew said in its report last year.

More recently, Cometfi.com, a website devoted to helping people manage their student loan debt, did its own analysis of census data and ranked which states have the highest per capita populations of young adults domiciled with their parents.

The study found that there's been an 18.7 percent increase in these types of living situations since 1997, and concluded that one of the main factors driving adults back to their parents' homes is the high cost of housing.

"Today, home prices, once considered a staple of the American dream, are rising twice as fast as income growth," Comet said in its report. "The cost of renting is also rising at the fastest pace in nearly two years."

That's one of the reasons states with relatively low housing costs and smaller populations also have the lowest percentage of adults living with parents. North Dakota, for example, came in last on the list, with 527.1 young adults living with parents per 10,000 young adults living in the state. Next lowest were South Dakota, Wyoming, Iowa and Montana.

Moreover, when Comet polled 64 random young adults on why there were residing with their parents, the top answer was saving money (87.5 percent), followed by student debt (42.9 percent) and "figuring out life" (35.7 percent).

Given these factors, some of the states that were on top of the list may not be all that surprising.

These states, in ascending order, had the highest percentage of young adults living with their parents, according to Comet:

10. Utah

1,053.2 young adults living with their parents per 10,000 in the state.