It is indeed 99%, according to the label that came with the rod.
I posted here sometime ago that I was apprehensive about lower carbon content in some JDM rods discussed. I believe it was about Lunakia. I must confess that the most sensitive rod that I've experienced since has a blank made of 96% carbon and 4% glass, so I've changed my opinion about carbon content quite substantially – many more factors go into building extremely sensitive blanks.