Indian national health surveys tell you, with reasonable precision, what is present in a working-age population of any given size. Almost none of it has been diagnosed. These pages set out what the published data says, where the cost actually lands on an employer, and what screening changes.
These are national adult prevalence figures from the ICMR-INDIAB study, scaled to a thousand-person workforce. Your real numbers move with age profile, location and job type, but this is the order of magnitude you are managing, whether or not it has been measured.
Written for the person who has to justify the budget, not for the patient. Every figure is sourced and linked.
These figures are a starting estimate, not your answer. The ROI calculator models the cost against your own headcount, age profile and premium, and a Health Risk Assessment replaces the estimate with what is actually there.