The breast cancer death rate was unchanged for decades prior to the onset of mammography screening, which began at a national level in the mid 1980's. As expected, five-to-seven years later, the death rate began to fall in 1990, and has now declined by over 30% since then. Each year, more than 30% fewer women die from breast cancer than would have died had the death rate not been reduced. Therapy has improved, but lives are saved when breast cancers are detected and treated earlier. It has been shown in studies from the Netherlands, Sweden, Norway and the United States that even when women have access to the latest therapy, it is screening that leads to the greatest reduction in deaths.