Level 1 data from Project Tycho, derived from all weekly notifiable disease reports for the United States dating back to 1888. These are the most complete and standardized data but for a limited number of diseases, locations, and years. Level 1 data includes counts at the state level for smallpox, polio, measles, mumps, rubella, hepatitis A, and whooping cough and at the city level for diphtheria. The time period of data varies per disease somewhere between 1916 and 2010. This version includes cases as well as incidence rates per 100,000 population based on historical population estimates.