Mortality from influenza increased from between 7,000 and 32,000 annual deaths in the 1970s, to between 36,000 and 72,000 annual deaths in the 1990s.
Thompson, William W., David K. Shay, Eric Weintraub, Lynnette Brammer, Nancy Cox, et al. Mortality Associated with Influenza and Respiratory Synctial Virus in the United States. JAMA. 2003; 289(2): 179-86. http://jama.jamanetwork.com/article.aspx?articleid=195750