A new study finds rates of breast cancer screening in the United States have dropped significantly. Mammographies were down 4 percent in 2005 nationwide. This comes after steady increases in screening, from 39 percent in 1987 to 70 percent in 2000.

Nancy Breen with the National Cancer Institute  says one reason may be insurance. Rates are climbing and fewer poor women have any. "The decline in health coverage for poor women is faster than in the general population of women 40 and older."

One surprise was a nearly seven percent drop in mammogram testing among women between 50-64 who have more income, education and greater access to health care. Breen says one reason might be complacency following well-publicized news reports that the incidence of breast cancer was on the decline. But she adds, "Those incidence rates are within the population and they don't have to do with risk. The risk of breast cancer is the same."

The risk, currently, is eight to one among American women. Each year 40,000 women in the United States die from the disease. Breen says mammography screening is the best tool to detect cancer early, when it is far more treatable. "Ninety-eight percent of women diagnosed with breast cancer at stage 1 are alive five years later."

Troubled by falling mammography rates, Breen says it is important to monitor the situation and develop appropriate interventions for why some women are not getting tested.

Mammograms are used to screen healthy women for breast cancer and, in combination with frequent self-exams, are recommended once a year for all women over the age of 40.