More than half of Americans, or 54 percent, are optimistic that President Donald Trump will do a good job of making the U.S. prosperous, found a latest Gallup poll.

However, Americans are less optimistic about Trump than about his predecessors Barack Obama (61 percent) and George W. Bush (66 percent), according to the poll.

Forty percent of Americans say Trump will do a poor job of making the country prosperous, compared to Obama's 30 percent and Bush's 23 percent.

In terms of environment protection, only 36 percent of Americans say Trump will do a good job, compared to 57 percent who believe he will do a poor job.

In comparison, 79 percent of Americans said Obama would do a good job of protecting environment in 2009 and 51 percent said Bush would do a good job in this regard in 2001.

When asked about energy policies, 46 percent of Americans say Trump will do a good job of improving the U.S. energy policies, while 48 percent say he would do a poor job.

In comparison, 72 percent of Americans said Obama would do a good job of improving the U.S. energy policies in 2009, while 58 percent said Bush would do a good job in this regard in 2001.

Trump has been less popular in general than either Obama or Bush at the start of their terms in office, so he might see less of a drop from expectations to ratings of actual performance than Obama or Bush did, Gallup noted.

"But his plans for action on the environment and energy will seemingly require real shifts in public opinion to succeed, given Americans typically view energy problems as less important than protecting the environment," Gallup said.

source: Xinhua