In a mass screening 1,329 men aged 40-59 years were examined with regard to serum cholesterol and systolic blood pressure, and then followed over a 6-year period for the development of coronary heart disease (CHD). At the beginning of the period all were free from CHD. Calculate the appropriate measure of occurrence for men with serum cholesterol under 220 mg/100 ml, and systolic blood pressure under 167 mm Hg.