The Centers for Disease Control and Prevention survey in 2009 and 2010 revealed a 27 percent decline over 10 years in the percentage of adults with high cholesterol, a major risk factor for heart disease that is the leading cause of death in the United States.

A similar survey conducted in 1999 and 2000 showed that 18.3 percent of adults had high total cholesterol.

The CDC survey did not study the causes of the decrease in high cholesterol. Likely factors include better diet, increased exercise and increased use of drugs that lower cholesterol levels, CDC epidemiologist Cynthia Ogden told Reuters.

While there are no symptoms associated with high cholesterol, levels in the blood can be monitored by a simple test.

There are two types of cholesterol. Low-density lipoproteins (LDL), known as "bad" cholesterol, can build up in arteries and cause heart disease, while high-density lipoproteins (HDL), called "good" cholesterol, can absorb the bad cholesterol and return it to the liver.

Both high total cholesterol levels or low HDL levels can increase risk of heart disease or heart attacks, the CDC said.

Despite the positive trends, the survey results were better news for some groups than others. More than 14 percent of women have high cholesterol compared to 12.2 percent for men, the CDC said.

Also, high total cholesterol is more prevalent in Hispanics, Ogden said. "Screening is less prevalent in that group than with whites, for example," he said.

The CDC survey for 2009 and 2010 included blood tests from 6,000 people.

(Editing by David Adams and Philip Barbara)

• A Permanent Economic Emergency