Over the past 30 years the Gallup organization has conducted 11 polls on the question of the origin and development of the human species. Over those eleven years the results have been remarkably consistent.
According to Gallup, 46% believe that God created humans in their present form; 32% believe that humans evolved, under the guidance of God; and 15% believe that human evolution took place absent any involvement by God.
When the question set was altered slightly, and the responses broken down by political party, the results were or as follows: 58% of Republicans polled believed God created humans in their present form within the last 10,000 years. Before you blow up your self-esteem to the bursting point note that according to Gallup 41% of the Democrats and 39% of the independents polled held the same view.
In sum, 46% of Americans hold the Creationist view of human origins within the past 10,000 years.
Most Americans are not scientists, of course, and cannot be expected to understand all of the latest evidence and competing viewpoints on the development of the human species. Still, it would be hard to dispute that most scientists who study humans agree that the species evolved over millions of years, and that relatively few scientists believe that humans began in their current form only 10,000 years ago without the benefit of evolution. Thus, almost half of Americans today hold a belief, at least as measured by this question wording, that is at odds with the preponderance of the scientific literature.