(NEW YORK) -- It's a growing trend. The number of couples co-habitating has risen 13 percent in the past year, to include 7.5 million couples. But a new study suggests, combining households doesn't always save people money.
A review of census data by the Pew Research Center finds household income for co-habitants without college degrees is about the same as those who live alone.
Living together does pay off for college-educated co-habitants, whose household incomes are about $15,000 higher than those who don't live with partners, and $5,000 more than married couples.
Scientists say the less-educated tend to marry younger, possibly divorce sooner and are more likely to be left with children, while degree holders are often two-income earners.
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