The dollar index slipped today, putting it on track to fall for a fifth week, the longest stretch of declines in four years, as disappointing data on domestic factory activity and consumer sentiment stirred doubts about the U.S. economic growth.

Earlier, this measure of the greenback against a group of currencies including the euro and yen .DXY bounced from a four-month low as buying emerged with lower European bond yields, and as traders booked profits on this week's gains in other currencies against the greenback.

"The dollar is oversold. The data weren't all that great, but the story is people still see the Federal Reserve raising interest rates later this year," said Kathy Lien, managing director at BK Asset Management in New York.

The euro was up 0.2 percent to $1.1431 EUR=, a tad below a three-month high of $1.1445 on Thursday and about 9 percent higher than a 12-year low of $1.0457 reached on March 16. That was the day the European Central Bank embarked on its 1.1 trillion euro bond-buying program, to which President Mario Draghi reiterated his commitment on Thursday.

The euro's rebound was partly helped by improved euro zone data and rising inflation expectations.

On the other hand, dollar bulls have been disappointed by a recent spate of U.S. data. First-quarter growth has been lackluster and there has been little evidence of a rebound in the second quarter.

On Friday, data on New York state manufacturing and readings on industrial output fell short of expectations, while a private gauge on U.S. consumer sentiment unexpectedly fell to its lowest in seven months in early May.

This down shift in the U.S. economy has helped stem a recent global bond market rout, which has narrowed the yield gap between Bunds and U.S. Treasuries and helped revive the euro.

The gap between 10-year Bunds DE10YT=RR and Treasuries US10YT=RR narrowed to 153 basis points, from around 180 bps about a month ago, making the euro more attractive to investors.

Against the yen, the dollar was up 0.1 percent at 119.24 yen JPY=, shaving its weekly loss to 0.5 percent.

The sterling was little changed at $1.5781 GBP=D4, leaving it with a weekly gain of 2.1 percent.

The Aussie dollar AUD=D4 fell 0.4 percent to $0.8044 after hitting a near four-month high of $0.8164 on Thursday.