Just saw a report today. Between 2011-2013 The CDC surveyed over 10,000 people ages 18-44 and asked questions about sexual attraction, sexual experiences and identity orientation.http://i2.cdn.turner.com/cnn/2016/images/01/06/nhsr88.pdf
The word "asexual" does not appear in the report.
The idea of not having sexual attraction to anyone doesn't appear in their report, really, either.
Their options for identity? Straight/homosexual, homosexual/gay/lesbian, bisexual and "don't know." (About 1% of their sample either answered "don't know" or did not answer that question.
There's no way for an asexual to answer that question. I "know."
Apparently they used to also offer a "something else" category but stopped in 2008 because less than 1% of people identified as "something else" and so that didn't affect their distribution of sexual identity.(http://www.cdc.gov/nchs/data/nhsr/nhsr036.pdf
For attraction, they offered "only attracted to men," "mostly attracted to men," "equally attracted to women and men," "mostly attracted to women," "only attracted to women," and "not sure."
There's no way for an aromatic asexual to answer that question either, because I'm definitely "sure."
Here's hoping the CDC will decide to count us next time?