A series of U.S. government regulations since 1964 has helped decrease the number of smokers. Spencer Platt/Getty Images

Fifty years after Dr. Luther R. Terry first warned Americans about the dangers of smoking in his landmark surgeon general’s report in 1964, the federal government has made huge strides in persuading Americans to quit: Smoking rates among adults have plummeted to 18 percent, from 42 percent in 1964.

But this year’s surgeon general’s report about the health consequences of smoking emphasizes that the battle against smoking is far from over and issues a challenge to eliminate it altogether.

Surgeon General Boris Lushniak told reporters Friday that the nation must push even harder to eradicate smoking, with the goal of cutting the cigarette smoking rate down to 12 percent by 2020. "Enough is enough," he said.

The report, which was formally released by the White House on Friday morning, says, “For the United States, the epidemic of smoking-caused disease in the 20th century ranks among the greatest public health catastrophes of the century, while the decline of smoking consequent to tobacco control is surely one of public health’s greatest successes ... However, the current rate of progress in tobacco control is not fast enough, and much more needs to be done to end the tobacco epidemic.”

The report compiles the last 50 years of research on smoking and its effects on nearly every organ of the body. It describes the public-health efforts to curtail smoking, which have included bans on smoking indoors, the elimination of cigarette ads on television and heavily taxed cigarette purchases.

The result is that “Americans’ collective view of smoking has been transformed from an accepted national pastime to a discouraged threat to individual and public health,” Department of Health and Human Services Secretary Kathleen Sebelius wrote in the report. “Strong policies have largely driven cigarette smoking out of public view and public air space.”

But more needs to be done, and the surgeon general vowed to accelerate polices aimed at making the U.S smoke-free.

“We will explore endgame strategies that support the goal of eliminating tobacco smoking, including greater restrictions on sales," the report stated.

The surgeon general’s office wrote that more than 20 million Americans have died from smoking-related illnesses in the last 50 years.

Some 2.5 million of those people were nonsmokers who died from heart disease or lung cancer caused by secondhand smoke, the report said. And exposure to secondhand smoke increases the risk of stroke by 20 to 30 percent, the report found.