Data is only compiled from one retailer. You can't base sales figures as an overall picture on one retailer.
Do you have a link or anything that shows worldwide sales or based on more retailers.
I am looking through google but all results seem to be very old.

I found this
http://www.highdefdi...show/Disc_SalesAlso
http://www.geek.com/...-of-disc-sales/ It doesn't seem to bear out 2:1 in favour of HD-DVD sales but more the opposite.
I expect DVD will have sold many more than both put together.