The number of people who have a relationship with their spouse is growing and the trend is reaching an apex, according to a new study by the National Bureau of Economic Research.

In the next 10 years, the percentage of people in relationships with spouses will double, the researchers said in their new paper.

They believe the shift in relationships will take place at an accelerating pace, with the average number of relationships doubling every 10 years.

The study is the first to explore the trend and its causes.

In the study, researchers analyzed data from the U.S. Census Bureau’s American Community Survey from 2005 to 2012.

They found that the number of couples in relationships had been increasing steadily from about 3.6 million to 5.5 million by 2012, reaching an average of 5.4 million in the 10 years that followed.

This year, the average for married people is 5.9 million.

But the increase in marriages is driven by people in their 30s and 40s, which have grown into the largest groups.

The proportion of adults between the ages of 30 and 44 in a marriage has increased from 16.5 percent in 2005 to 18.2 percent in 2012, according the study.

The increase in the proportion of married people in a relationship has been increasing at a much slower rate than the proportion in relationships.

For example, in 2005, 28.4 percent of married couples were living together and 28.2 of those people were in relationships, the study found.

The trend is accelerating among younger people, too.

The number and percentage of adults age 18 to 34 in a long-term relationship has risen from about 8.4 to 11.4 over the same period, according a report released Thursday by the Pew Research Center.

That’s because many young people are starting families and finding themselves with new responsibilities, said Andrew Cherlin, the lead author of the Pew report and an associate professor at Columbia University.

Cherlin said he thinks the rise in long-distance relationships will be a boon to the economy, because they offer people who are having trouble finding a partner an outlet to meet people.

The rise in people who live with their parents is also encouraging, said Cherlin.

“They’ve got lots of choices,” Cherlin told Fortune.

“And they don’t necessarily want to have to choose between that and finding a spouse.”

The rise in the number and rate of long-lasting relationships may also be driven by a growing number of singles.

The National Marriage Project, which studies long-living relationships, estimates that about 2 million people ages 18 to 49 are currently in long lasting relationships.

About 1.2 million people are in marriages with someone who is married.

The rate of people age 50 and older who are in long enduring relationships is nearly double the rate of those younger than 50.

This study is one of the first comprehensive estimates of the trends in long term relationships and their effect on the economy.

Researchers from the Brookings Institution, the National Economic Research Associates, and the Brookings National Bureau found that there is a clear correlation between people in long distance relationships and the economy and that the relationship patterns reflect economic fundamentals that are generally improving.

But the study also found that it’s not a straightforward equation.

While the number, rate, and number of long lasting partners varies greatly across the U