Washington ? For love or money? The number of unmarried couples living together is rising sharply as many young adults who are having a hard time finding jobs are now “doubling up” with significant others.

The number of opposite-sex unmarried couples who shared living arrangements jumped 13 percent this year to 7.5 million, the Census Bureau reported Thursday. That’s compared with a 2 percent decrease between 2008 and 2009.

There were about 620,000 same-sex couples living together, a figure not statistically different from a 2008 census estimate of 565,000.

Demographers say a sluggish job market is the likely factor. Many young adults turned first to friends and parents for financial help since the recession began in late 2007, and may now be leaning on boyfriends or girlfriends as unemployment benefits and savings accounts dwindle in the prolonged economic downturn.

“It would be odd to say this year was emotionally different, so it’s more likely practical considerations that are behind the increase in cohabitation,” said Rose Kreider, a family demographer at the Census Bureau who reviewed the numbers.

Her analysis, published Thursday in a 19-page census working paper previewing the 2010 data, shows that newly formed unmarried couples living together were more likely to have one partner unemployed, who was often male. They also typically lived in the South where poverty was more widespread and sometimes in larger households, such as with parents or other couples.

The findings come after the Census Bureau reported last week that the U.S. poverty rate jumped in 2009 to 14.3 percent, or 43.6 million people, the highest since 1994.