For people with TB infection, no risk factors, and no treatment, the risk is about 5% in the first 2 years after infection and about 10% over a lifetime.
Figure 2.5 Risk of Developing TB Disease Chapter 2. Page 32
Core Curriculum on Tuberculosis: What the Clinician Should Know
Sixth Edition 2013
Centers for Disease Control and Prevention
National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention
Division of Tuberculosis Elimination