I certainly have not counted the number of all diabetics in the world but I have read a lot of articles reporting a way higher number already than the 330 million by 2030 for example this one which says
that today there are 69million living with diabetis in India and a 110 million in China. By 2040 the total number worldwide is around 640million cases.

And there is this discussion going on about the number of prediabetics and if today's numbers should include 100 Million cases of yet undiagnosed cases for instance amongst indigene populations etc.

http://www.medscape.com/viewarticle/855296