The third column is the enrollment of 12/21/2012.
The other day (11.18.2016) I met a graduate of the Seaford High School class of 1965. He said his graduating class numbered 320. In vast parts of Nassau County that had farms or vacant land in the early 1940's, there was a housing boom through the 1950's that caused a peak in high school enrollment in the 1960's. By the 1970's, districts were dismissing staff and closing schools.