This graphic shows the change in the area of the United States affected by increases in the proportion of total annual precipitation derived from extreme daily precipitation events (more than 2 inches). The x axis represents 20-year increments, starting from 1900 through 2000. The y axis shows percent area of the nation experiencing extreme precipitation events (e.g., storm) in 2 percent increments, starting from 6 percent to 14 percent area.