Whole NPCdata contains only 2 types of information, mobs stats and drop groups. L2wiki doesn't contain this groups, it's just giving you list of dropping items. Based on chance of group drop and chance of item in this group drop - item will have certaint chance to drop. Like if in group you have 3 items, each with 33% chance to drop and group drop is 10%, then each item, based on l2wiki, will have 3.3% chance to drop.
Both types of information, mobs stat and drop groups, are important and we can't share it.