NEW YORK (CNN/Money) - President Bush has lost ground in the public relations battle over Social Security since he kicked off a concentrated campaign two months ago to convince Americans the national retirement program needs an immediate overhaul, according to a recent poll.

A CNN/USA Today/Gallup poll conducted Friday to Sunday said 38 percent of Americans feel major changes must be made in Social Security within the next two years. In January, that number was 49 percent.

Bush has made reforming Social Security, which includes a contentious plan to put some of the program's money into the stock market, a key part of his second-term agenda.

Other numbers in the poll don't play out so well for the president, either. Forty-seven percent of those polled trusted the Democratic Party to deal with the issue of Social Security benefits, while 37 percent trusted Republicans.

And 75 percent held a favorable opinion of the AARP, the retirement association that has taken a lead role in opposing the president's plan.

However, 75 percent of those polled said major changes to Social Security are needed within the next ten years.