An epidemiologic study examined the incidence of symptomatic Chlamydia infection in a cohort of 2000 young women in a county in Georgia over 5 years. All subjects were enrolled on the same day (Jan 1, 2015), and did not have Chlamydia infection at the time of study enrollment. During the study period, 440 subjects were newly diagnosed with Chlamydia infection. Subjects were followed for a total of 6200 person-years. If no one dropped out of the study and no one developed Chlamydia infection during the study period, how many person-years would be contributed in total by subjects in this study?