One in five people in the US population is not developing diabetes like they used to — the first sustained improvement in 25 years.

The number of new cases of the disease has fallen by nearly 20% in the last seven years, according to new figures released in December by the Centers for Disease Control and Prevention. In 2014 alone there were 300,000 fewer new cases than the 1.7 million recorded for one year in 2008.

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Health officials aren't sure what exactly is causing the decline, but it parallels changes in Americans' eating and exercise habits.

Studies indicate people are drinking 20% less soda than in 1998, the number of people exercising regularly has increased by 17% since 2001, and children are consuming 5.5% fewer calories on average than they did in the 1990s. Another impressive trend: childhood obesity rates have plummeted by more than 40% over the last decade.

"It's not yet time to have a parade," Dr. David Nathan, Director of the Diabetes Center at Massachusetts General Hospital, told the New York Times. "[But] it has finally entered into the consciousness of our population that the sedentary lifestyle is a real problem, that increased body weight is a real problem."

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