MONDAY, Dec. 15 (HealthDay News) -- U.S. death rates for heart disease and stroke have dropped by about 30 percent since 1999, according to the latest American Heart Association statistics.

The improvement comes even though more Americans are sedentary and obese than ever before, experts noted.

"Our work isn't done, since the major risk factors for heart disease and stroke have not seen the same declines as the death rates, and several [risk factors] are rising," AHA President Dr. Timothy Gardner said in an association news release.

Still, between 1999 and 2006 there was a 30.7 percent decline in coronary heart disease deaths and a 29.2 percent drop in stroke deaths.

The findings were published online Dec. 15 in the AHA journal Circulation.

Despite the recent drop, cardiovascular conditions such as heart attacks and stroke remain the leading cause of death in the United States, accounting for 34.2 percent of the more than 2.4 million deaths reported in 2006.

And statistics for Americans with heart risk factors remain static. For example, while average cholesterol levels for men 40 and older and women 60 and older dropped from 204 mg/dL to 199 mg/dL between 1999 and 2006, little change was seen for other age groups, the AHA report noted.

Most Americans aren't exercising, either. Nearly two-thirds (62 percent) of adults reported no vigorous daily activity lasting at least 10 minutes in the 2006 National Health Interview Survey. That exercise threshold is the minimum recommendation for heart-strengthening exercise.

And yet the AHA says it has still met its goal of reducing coronary heart disease and stroke by 25 percent by 2010.