The improvement was due a decline in smoking, better treatment and earlier detection, it said.
The group predicted 1,529,560 new cancer cases in the United States in 2010 and 569,490 deaths.
Death rates for all cancer types fell by 2 percent a year from 2001 to 2006 among men and 1.5 percent per year from 2002 to 2006 in women, it said.
New cases of colorectal cancer fell 3 percent a year in men and 2.2 percent a year for women from 1998 to 2006, while lung cancer rates have fallen in men by 1.8 percent each year since 1991 and finally started leveling off among women.
"We will build on our progress in the fight against cancer through laws and policies that increase access to cancer prevention, early detection, and treatment services, and with a sustained federal investment in research designed to find breakthroughs in the prevention and treatment of the most deadly forms of cancer," John Seffrin, chief executive officer of the American Cancer Society, said in a statement.
The full report is available at http://caonline.amcancersoc.org/papbyrecent.dtl.
FALLING MORTALITY RATE
The drops in mortality rates have meant 767,000 people who would have died prematurely from cancer over the past 20 years did not, the organization said.
The overall U.S. death rate from cancer in 2007 was 178.4 per 100,000 people, a 1.3 percent drop from 2006, when the rate was 180.7 per 100,000.
"In that time, mortality rates have decreased by 21 percent among men and by 12 percent among women, due primarily to declines in smoking, better treatments, and earlier detection of cancer," the group said in a statement.
Lung cancer remains the No. 1 cancer killer of both men and women in the United States. Breast cancer comes in No. 2 for women, prostate cancer is the second most common killer of men, and colon cancer is the third leading cause of cancer death for both sexes.
On Tuesday, the U.S. Centers for Disease Control and Prevention said at least 10,000 people and possibly far more die in the United States each year because they have not been screened for colon or breast cancer.
The cancer society projects that 222,520 Americans will get lung cancer in 2010 and 157,300 will die. It says 102,900 will get colon cancer and 51,370 will die from it; 209,060 will get breast cancer and 40,230 will die; and 217,730 will get prostate cancer and 32,050 will die from it.
(Editing by David Storey)