Rare disease patients outnumber cancer patients

I saw this blog post on the Nord website: http://blog.rarediseases.org/the-solution-to-diagnostic-delay-may-be-closer-than-we-think/ which has an interesting point of view. I was a little surprised to find that rare disease patients outnumber cancer patients by about two to one. (this is a US number, and the comparisons in the blog post relate to the US cancer/rare disease population).

The stats for cancer in the US are here: http://www.cancer.org/cancer/cancerbasics/cancer-prevalence, with various stats for rare diseases on the Nord blog. I suppose that this arises because this is a comparison with~7000 rare diseases and ~200 cancers.

I like the point of view presented here - essentially that doctors ought to be more aware of the potential for rare diseases, but I can also see the other side - to me it makes more sense for doctors to know the more common stuff inside out.