American Cancer Society researchers revealed in a new report published Wednesday that the U.S. cancer death rate dropped 2.2% between 2016 and 2017, the largest decline recorded in national cancer statistics dating back to 1930, AP reports.

The big picture via Axios' Bob Herman: Lung cancer drove most of the decline, as fewer people smoke cigarettes, and advanced lung cancer treatments become standard. Lung cancer accounts for nearly a quarter of all cancer deaths, according to the lead author of the report, Rebecca Siegel.

Cancer death rates had been falling by roughly 1.5% every year since 1991.

Why now: Experts say there have been many advances in treatment, specifically in surgery, diagnostic scanning and more exact uses of radiation, AP notes.

The overall cancer death rate dropped 30% from 1991 to 2017, per Cancer Society researchers.

A decline in death rates associated with breast, colon and prostate cancer is also slowing, AP writes.

Worth noting: Government researchers have reported a slightly lower fall in cancer deaths for the same period, but the Cancer Society calculates the death rate differently, per AP.

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