A 4-year prospective cohort study was conducted to examine the relationship between sedentary behavior and the incidence of type 2 diabetes among 1,800 individuals at-risk. Of these, 497 were followed for 1 year, 661 were followed for 2 years, and 642 were followed for the full 4 years. By the end of the study, 270 participants had been diagnosed with type 2 diabetes during the 4-year period. Calculate the incidence density rate per 100 person-years. Please give your answer rounded to the 10th decimal place.