The aircraft is arguably on the large side at 266 seats but loads have been fairly good, I think
Looking back to May-Dec 2015, based on the CAA stats, the highest months LFs were:
May (82%); Aug. (86%); Sep. (86%); and Oct. (85%)
The version of the B763 that DL used previously was usually 226 seats in total (26 in J class) although the 208/211 seat version (36 in J class) was occasionally used.
The average VS load exceeded 226 in Aug. & Sep. with Oct. at 225.
The other months were:
June 75%; July 73%; Nov. 75% and Dec. 73% assuming all flights operated daily, although I believe frequency does drop slightly for part of the winter.