Every influenza epidemic, between 55,000 and 431,000 Americans are hospitalized, with a mean annual hospitalization rate of 226,000.
Thomas, Cindy P., Marian Ryan, John D. Chapman, William B. Stason, Christopher P. Tompkins, et al. Incidence and Cost of Pneumonia in Medicare Beneficiaries. Chest. 2012; 142(4): 973-81. http://journal.publications.chestnet.org/article.aspx?articleid=1215975