Poll: 16% still think Obama not born in America

A new poll indicates that 16 percent of likely voters still don't believe President Obama was born in the United States, even after the release of Obama's purported long-form birth certificate.

The Zogby poll also shows 30 percent of Republicans not believing the president has proven his American birth.

Last week, on April 27, Obama posted an image of what he claims to be his original, long-form Certificate of Live Birth from the state of Hawaii, noting he was born in Honolulu at 7:24 p.m. on Aug. 4, 1961.

The four-day survey was taken April 29-May 2.

Demographic groups besides Republicans expressing the highest levels of doubt about Obama's birth in the U.S. are conservatives at 34 percent, and those without a college degree, at 21 percent, vs. those with a degree, at 11 percent.

The interactive poll of 2,020 likely voters has a margin of error of +/-2.2 percent.

On April 26, the day before the release of the long-form birth certificate, a USA Today/Gallup poll revealed only 38 percent of Americans were convinced Obama definitely was born in the U.S. and another 18 percent said he probably was.