An epidemiologist is evaluating a newly implemented screening program for hypertension in a factory with 10,000 workers. On the first screening day (baseline), 1,200 workers are found to have hypertension. Over the next 12 months, among the 8,800 workers who were initially hypertension-free, 440 develop hypertension. The epidemiologist wants to determine which investigation/measure would be most appropriate to quantify the *new occurrence* of hypertension in this initially disease-free cohort.