Well, according to this article
, in February of 2009, something like 22% of Facebook users were over the age of 35. In addition, the fastest-growing groups on Facebook were (in order) those 45-54 years old (+165.8%), those 35-44 years old (+138.7%) and those 55+ years old (+137.8%). And these sorts of growth rates have been pretty consistent from at least late 2007 on.
Of course, Facebook isn't "the Internet," but it's on
You might also find some useful information in one of the charts found in this PDF released by Nielsen Online in August 2008
. Indicates that about half of all Internet users are over the age of 35, including 23% over the age of 55. Not only are older folks (myself included) a large group online, they spend more time online than those in younger age groups.
Scroll down to the second page to see the age breakdown.
This is apparently a pretty consistent result. I also found this article from 2006
, showing that those over the age of 50 represented the largest age group online.
HTH dispel some of the "older folks aren't online" myths under which your client is currently laboring...