This graph shows that the incidence of CRC has been declining since the mid-1980s. This is thought to be due to changing patterns of risk factors, such as smoking, as well as increased CRC screening. The rate of decline has increased in recent years due to increased detection and removal of precancerous polyps. CRC death rates have been decreasing since 1980 in men and since 1947 in women. These declines are thought to be due to improvements in treatment as well as changing patterns in risk factors and screening. The rate of mortality decline has also increased in recent years.