The waistlines of Americans continued to expand in 37 states over the past year, with no state seeing a decrease in obesity rates, according to a report released Tuesday.

More than 25 percent of adults are obese in 28 states, an increase from 19 states last year, Trust for America’s Health and the Robert Wood Johnson Foundation reported in their fifth annual obesity survey. More than 20 percent of adults are obese — 30 pounds or more overweight — in every state except Colorado.

Nine of the Top 10 fattest states are in the south. Mississippi leads the pack with an adult obesity rate of 31.7 percent, according to the report, which is a follow-up analysis of the annual Behavioral Risk Factor Surveillance Survey by the federal Centers for Disease Control and Prevention.

"Our analysis shows that we’re not treating the obesity epidemic with the urgency it deserves,” said Jeff Levi, executive director of TFAH, in a news release. “Even though communities have started taking action, considering the scope of the problem, the country’s response has been severely limited. For significant change to happen, combating obesity must become a national priority.”

Mississippi is followed by West Virginia with a 30.6 percent obesity rate, Alabama with 30.1 percent, Louisiana with 29.5 percent and South Carolina with 29.2 percent. Michigan, which comes in at No. 10, is the only state to crack the Top 10 that is not in the South.

Colorado has the lowest adult obesity rate at 18.4 percent. Hawaii had the second-lowest rate at 20.7 percent, followed by Connecticut at 20.8, Massachusetts at 20.9, and Vermont at 21.1.

Obesity rates have steadily climbed over the past 28 years. In 1980, the national average of obese adults was 15 percent, according to the report. And, in 1991, no state had an obesity rate above 20 percent. Now, an estimated two-thirds of American adults are overweight or obese, and an estimated 23 million children are either overweight or obese, the report said.

Diseases associated with obesity, like type 2 diabetes and high blood pressure, are also on the rise. Rates of type 2 diabetes increased in 26 states last year.

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States With the Highest Obesity Rates

1. Mississippi

2. West Virginia

3. Alabama

4. Louisiana

5. South Carolina

6. Tennessee

7. Kentucky

8. Oklahoma

9. Arkansas

10. Michigan

States With the Lowest Rates

1. Colorado

2. Hawaii

3. Connecticut

4. Massachusetts

5. Vermont

6. Rhode Island

7. Montana

8. Utah

9. D.C.

10. New Jersey

The Associated Press contributed to this report.