The 7% figure is probably dedicated players. The real advantage that Blu-ray had over HD-DVD was the PS3. I bought my PS3 because I wanted a Blu-ray player and it was the highest quality for the money ($300).
EDIT: After looking at the link, I am correct. They seperated HD-DVD and the external drive, and they seperated Blu-Ray and the PS3. If you assume no overlap, 16% are capable of playing Blu-Ray, while only 14% are capable of playing HD-DVD. Either way the race in the United States was very close, compared to other countries where Blu-ray was the clear winner.