"Type 2 diabetes is still a rare condition [in children]."To date there are no nationally representative data on the prevalence of type-2 diabetes in children. The best information the CDC offers is: "Health care providers are finding more and more children with type-2 diabetes, a disease usually diagnosed in adults aged 40 years or older."
-Centers for Disease Control and Prevention, 2005
While there may be an increase in diagnosis, that does not necessarily imply that the absolute number of cases is high. Essentially, every study attempting to measure the prevalence of childhood type-2 diabetes has looked only at specific minority populations. The closest thing to a representative sample comes from a study based in Cincinnati, which found that 7.2 of every 100,000 children have type-2 diabetes.