The Secular Coalition for America on Tuesday released a presidential candidate scorecard, rating the candidates' public statements and actions in five categories.

“This scorecard shows that our current politicians still have a long way to go in protecting the secular values that America was founded on,” said Edwina Rogers, Executive Director of the Secular Coalition.

Republican presidential candidate Mitt Romney received a failing grade, while President Barack Obama received a "C." Libertarian presidential candidate Gary Johnson received the highest grade, a "B," and Green Party candidate Jill Stein received an "incomplete."

The Secular Coalition for America noted that Romney has insisted the United States is a Christian nation, and thinks the concept of the separation of church and state has been taken "well beyond its original meaning." Romney has also said his faith would inform his decision as president, was a supporter of the controversial Blunt Amendment, fought for abstinence-only sex education, and promoted government funding for faith-based organizations.

However, Romney earned two individual "A" grades and some "C" grades. The GOP candidate has said that nonbelievers can be just as moral as believers. He has also said he would be willing to appoint an atheist or agnostic judge, and that evolution -- not creationism -- should be taught in science classes.

While Obama fared much better than Romney, particularly when it came to health care issues, the Secular Coalition for America noted that he too has said his faith informs his decision as president. The President also had promised to end hiring discrimination within faith-based organizations, but has failed to take action. Like Romney, Obama supports the term "Under God" in the Pledge of Allegiance and "In God We Trust" as the National Motto.

“Last week we learned that now nearly 20 percent of Americans are religiously unaffiliated. Too often we see lawmakers shy away from the non-religious, but the statistics show that lawmakers can no longer afford to ignore us,” Rogers added.

According to a Pew Research survey, Americans who claim no religious affiliation is at an all-time high, growing from 15 percent in 2007 to nearly 20 percent in 2012.