Sarah,

FTE stands for full-time equivalent.  It is comprised of the amount of staff that equals 8.5 employees.  8.5 could be 6 full-time employees and 5 employees at 50%, it could be 7 full-time employees and 2 employees at 75%, or 8 full-time employees and 1 employee at 50%.  But it all adds to the the equivalent of 8.5 full-time employees.

Dee Harris