216 HS sent about 2.7 students/HS)

1,361 new freshmen arrived at Yale as the members of the Class of 2018

1,361 - 776 = 585 students from 216 HS ( those HS sent about 585/216 = 2.7 students/HS)
992 - 776 = 216 high schools 
 
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Tuesday, July 15, 2014
Class of '18: 992 High Schools 
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In July, Yale reported that 992 different high schools will send students to
become members of the Class of '18.  At least 57% (or 776 students) will be
the only student in the freshman class from his/her school.