A sample of 7,000 men, 40 years of age or older were examined in January 2000. Of these, 2,000 lived in areas where they were exposed to high levels of air pollution and 5,000 lived in areas with low levels of air pollution. At the initial examination, 250 cases of chronic bronchitis were discovered; 100 among participants living in areas with high levels of air pollution and 150 among those in areas with low pollution. All the men initially examined who did not have chronic bronchitis were available for subsequent repeated examinations during the next 10 years. These examinations revealed 220 new cases of chronic bronchitis and of those 130 lived in areas with high levels of air pollution while 90 lived in areas with low pollution levels.

What is prevalence of chronic bronchitis among men 40 years of age or older who lived in areas with high levels of air pollution in January 2000?

	A.	50 per 1000
	B.	18.2 per 1000
	C.	5 per 1000
	D.	110 per 1000 person-years
	E.	110 per 1000