(Photo by Michael Temchine/For The Washington Post)

Two-thirds of smokers will die early from cigarette-triggered illness -- unless they choose to kick the habit, according to new research from Australia.

The study of more than 200,000 people, published this week in BMC medicine, found about 67 percent of smokers perished from smoking-related illness. That rate is higher than doctors previously estimated.

Tobacco smoke can boost the risk for least 13 types of cancer. The earlier you quit, the better.  “The relative risks of adverse health effects increase with increasing intensity of smoking,” the study states, “measured by the amount of tobacco smoked per day, and with increasing duration of smoking.”

Smoking 10 cigarettes daily doubles the risk of death, the research showed. Smoking a pack daily quadruples it.

"We knew smoking was bad, but we now have direct, independent evidence that confirms the disturbing findings that have been emerging internationally," said co-author Emily Banks, a researcher at the Australian National University.

An estimated 42.1 million Americans smoke cigarettes, according to the Centers for Disease Control and Prevention. Cigarette smoking is the top cause of preventable disease and death in the United States, the agency reports, accounting for more than 480,000 deaths every year -- or one in five.

Emotional turmoil aside, smoking is also bad for our wallets. An Ohio State University study found employees who smoke tobacco cost employers roughly $6,000 more annually in health care and productivity than nonsmokers.

Another study, from the New England Journal of Medicine, shows health-care costs for smokers tend to be, on average, 40 percent higher. (The same research darkly suggests we’d all save money in the short term if cigarettes vanished from earth but might pay more down the line because everyone would live longer.)

Policymakers have long wondered how to get Americans to quit the habit. Adding excise taxes to cigarette packs has reduced youth smoking in some areas, according to research from the University of Michigan. Nearly 30 percent of adults who live below the poverty level smoke, compared with 16 percent who live at or above the poverty level.

The World Health Organization recommends enforcing smoke-free public places and creating “supportive environments” for people to part with their packs. The CDC, meanwhile, distributes advice like “how to live with a hole in your neck.”