This excellent 2013 study gives updated results as of 2013 for diabetes diagnosis stats (and likely prediction) for subjects who took the 5 Trialnet autoantibody tests, but looks at it by subject age instead of number of years after testing. The population size is large (more than 15,000).

Here is the statistics curve, with a 15-year+ horizon:

courtesy Ziegler AG, Rewers M, Simell O, et al. Seroconversion to Multiple Islet Autoantibodies and Risk of Progression to Diabetes in Children.

JAMA.2013;309(23):2473–2479. doi:10.1001/jama.2013.6285

- The lowest line, solid, shows the progression statistics for subjects (almost all children I gather) with zero positive Trialnet antibody tests. Their likelihood of developing diabetes by age 15 is extremely low:

Diabetes risk by 15 years of age was 0.4% (95% CI, 0.2%-0.6%) in children with no autoantibodies

- The second line, long dashes, shows the progression statistics for children with one positive Trialnet antibody test. Their likelihood of developing diabetes by age 15 is low but not negligible:

Diabetes risk by 15 years of age was […] 12.7% (95% CI, 8.9%-16.5%) in children with a single islet autoantibody

- The third line, small dashes, shows the progression statistics for children with two positive Trialnet antibody tests. Their likelihood of developing diabetes by age 15 is high:

Diabetes risk by 15 years of age was […] 61.6% (95% CI, 53%-70.2%) in children with 2 islet autoantibodies

- The fourth line, very small dashes, shows the progression statistics for children with three positive Trialnet antibody tests. Their likelihood of developing diabetes by age 15 is very high:

Diabetes risk by 15 years of age was […] 79.1% (95% CI, 73.3%-85%) in children with 3 islet autoantibodies

Do note, however, that, while the total enrolled population is very large, there is only a small number of children testing positive to two and three autoantibody tests (respectively 19 and 20 subjects). Nonetheless, the trend is unmistakable