OK, how many HDTVs are there really?

[BillCable]

OK, I'm stumped by some very contradictory info. I'm hoping somebody here can shed light on it.

According to the Consumer Electronics Association, at the end of 2007 there were predicted to be 53 million HD-TVs sold in the USA.

http://www.ce.org/Press/CurrentNews/...l.asp?id=11309

According to Pacific Media Associates, there will be 113 million HD-ready displays by the end of 2008, up 40% from current numbers. That'd peg the current number at 80 million. I'm assuming a big chunk of those are computer monitors rather than HD-TVs.

http://www.dvdfile.com/index.php?opt...k=view&id=6496

Those two pieces of data sort of line up, assuming 30 million computer monitors. I'd be happy with those if not for the Nielsen data. Nielsen states that there are only 15 million HD-TVs in the US, a mere 13.7% of US households!

http://www.nielsenmedia.com/nc/porta...00ac0a260aRCRD

How can one agency conclude there are over 50 million HD-TVs in the US, while another concludes there are just over 15? The difference there is just inexplicable. The CEA data is THREE TIMES GREATER than the Nielsen!

I was hoping somebody here could explain this. How can they be so different? Is one just flat-out wrong?