According to the survey conducted in January, 18 percent of online adults have had personal information stolen such as their social security number, credit card or bank account information. That's up from 11 percent in a July 2013 Pew survey.
The number of adults who had an online account compromised or taken over without their permission such as email or social media remained flat at 21 percent.
The survey was done after news broke of Target Corp.'s massive pre-Christmas data breach, but well before last week's discovery of the "Heartbleed" bug, which has caused widespread worry across the Internet.
The Target breach resulted in the theft of 40 million debit and credit card numbers, along with the personal information of up to 70 million people. The cost of replacing potentially stolen debit and credit cards has already reached into the tens of millions of dollars.
Other companies including Neiman Marcus and Michael's subsequently reported their own smaller data breaches.
It remains unclear whether hackers have been able to exploit Heartbleed, which went undetected for more than two years, to steal personal information. The bug is caused by a flaw in OpenSSL software, which is used on the Internet to provide security for both websites and networking devices such as routers, switchers and firewalls.
The Pew survey, conducted between Jan. 23 and 26, polled 1,002 adults living in the continental U.S. It has a margin of error of plus or minus 3.5 percentage points.