At its conference in November, the NPD rejected a motion calling for the party to distance itself from the skinhead movement.
The data uses calculations based on NPD Group, which provides market research and analysis of retailers who sell video games.
At least five different forms of Niemann-Pick disease (NPD) have been identified.
In patients with types A and B NPD, there is a build-up of sphingomyelin in cells of the brain, liver, spleen, kidney, and lung.
Type A is the most common form of NPD and the most serious, with death usually occurring by the age of 18 months.