These graphs of unprovoked shark attacks for the United States from 1960 through 2016 show the portion occurring in Florida and Volusia County, currently the location of the most shark attacks worldwide.
The drop in recorded attacks in 1969 is a result of a loss of funding to support the ISAF, and hence less effort reporting and organizing of attacks (see The History of the International Shark Attack File). The apparent increase in attacks after 1987 is in part an artifact of the ISAF moving to the Florida Museum of Natural History, resulting in an increased scope of coverage and reporting of attacks.
The apparent increase in attacks after 1993 is in part an artifact of a breakthrough in communication with Volusia County (FL) emergency responders and lifeguards, resulting in the reporting of a greater number of minor attacks that had previously gone unreported. Volusia County, Florida has a high number of shark-human interactions as a result of extremely high aquatic recreational utilization of its waters by residents and tourists, especially surfers. Most of these interactions result in minor bites or abrasions from small sharks.
Unprovoked Shark Attacks in the United States Compared to Florida
Unprovoked Shark Attacks in Florida Compared to Volusia County