Time normalized data for CDC US Outpatient Influenza Surveillance: 1997-present

This is the publicly available data from CDC, current up to the end of week 41 (October 11-17, 2009).

CDC Current Weekly FluView Report
Archive of FluView Weekly Reports
CDC Historic Influenza Surveillance Data
Notes on the CDC data:
1. Some years contain a "week 53", the years without week 53 do not have that data point.
2. Some of the years only have data from week 40 to week 20 (approximately the months of October-April).
3. Starting in 2003-2004 influenza season data, the CDC began providing a weighted % ILI value, which is the data used in the plots from 2004 forward. Prior years use the unweighted CDC reported value.