Bold denotes real numbers from CDC, regular text is projected using exponential equation excel came up with as the best "equation" for the data.

y = 29e^.3164x

Where y = infected Americans and x = days. R^2 = .989



4/27/2009 40
4/28/2009 64
4/29/2009 91
4/30/2009 109
5/1/2009 141
5/2/2009 160
5/3/2009 226
5/4/2009 296
5/5/2009 403
5/6/2009 642
5/7/2009 896
5/8/2009 1,639
5/9/2009 2,254

5/10/2009 2,372
5/11/2009 3,250
5/12/2009 4,451
5/13/2009 6,097
5/14/2009 8,351
5/15/2009 11,438
5/16/2009 15,667
5/17/2009 21,459
5/18/2009 29,393
5/19/2009 40,259
5/20/2009 55,144
5/21/2009 75,531
5/22/2009 103,455
5/23/2009 141,704
5/24/2009 194,094
5/25/2009 265,852
5/26/2009 364,141
5/27/2009 498,768

Just found it interesting....