Although breast cancer remains the most common cancer afflicting women in the United States, the death rate associated with it is declining at a rate of about 2 percent a year, according to a report by the American Cancer Society (ACS).

According to the ACS, breast cancer rates have been declining since 1990.

“The steady drop in the breast cancer death rate means that this year alone, about 15,000 breast cancer deaths were avoided that would have occurred had rates not begun to drop,” said John R. Seffrin, PhD, CEO of the ACS. “Since the early 1990s, that decline adds up to more than 130,000 grandmothers, mothers and daughters who were alive, perhaps to celebrate another birthday, and even to go on to live a full, rich life.”

This year, the ACS reported, an estimated 192,370 new cases of invasive breast cancer will have been diagnosed among women, as well as 62,280 additional cases of in situ breast cancer. About 40,000 women are expected to die from breast cancer this year, making it the second most common cause of cancer deaths (behind lung cancer) in women

Between 1975 and 1990, the breast cancer death rate for all races combined increased by 0.4 percent annually. Since 1990, there has been a dramatic improvement in its death rate--between 1990 and 1995 the rate decreased by 1.8 percent annually, between 1995 and 1998, the rate decreased by 3.3 percent annually and between 1998 and 2006 the rate decreased by 1.9 percent annually.

Breast cancer death rates have dropped significantly for women under the age of 50—from 1990 to 2006 death rates decreased by 3.2 percent per year among women younger than 50 and by 2 percent per year among 50 and older. The phenomenon, according to the ACS, is credited to early breast cancer screening and advances in treatment. But gaps remain in incidences of breast cancer and death rates among different populations.

For example, while Caucasian women have higher incident rates of breast cancer than African-American women, those rates have dropped over the last decade at a rate of 2 percent annually. Meanwhile, the incident rate for African-American women has remained stable.

According to the ACS, the decline in breast cancer cases among Caucasian women may be due to the decreased use of postmenopausal hormone replacement therapy (HRT)—which, the ACS said, has been linked to an increased risk of breast cancer. The stable rate of breast cancer cases among African-American women may, said the ACS, be due to the fact this group’s use of HRT was already lower.

The ACS also reported that as of 2006, breast cancer death rates were 38 percent higher among African-American women than Caucasian women—a consequence of the fact that African-American women are more likely to be diagnosed at a later stage than Caucasian women.

The ACS recommends yearly mammograms and breast exams for women 40 and older. Women at high risk–those with a known family history of BRCA gene mutations, for example—should talk to their doctors about getting a breast MRI.