The data shows that the median size of a TV reviewed on CNET grew from 34 inches in 2002 to 46 inches in 2009.
Source: Blog post on Flowing Data, 29th September 2009
Note - this is more 'interesting' than 'scientific', but it seems to illustrate that the TVs in people's homes are getting bigger, which rings true for me.
From the blog post:
"The numbers come from the past 745 dated CNet television reviews. While reviews aren't a direct indicator of what televisions people buy, they do show what's on the market"