There are way too many variables for that to imply "programmers get fatter over time." 1) Maybe t-shirts sizes themselves are not the same between 1999 and 200

There are way too many variables for that to imply "programmers get fatter over time." 1) Maybe t-shirts sizes themselves are not the same between 1999 and 2008 2) Maybe the average age of the attender has not changed, so there's really no age component 3) Maybe a different demographic is now attending the conference 4) Maybe all Americans are fatter on average and programmers are just part of that trend