Figure 1. . . . . . Total number and rate of reported foodborne norovirus outbreaks per 1,000,000 person-years by affected states, United States, 2001–2008. Number given in each state indicates the total number of outbreaks over the 8-year study period; shaded boxes in key indicate the reported rate by quartiles. Multistate outbreaks are assigned as outbreaks to each state involved.