Durability of dropped weapons

Screenshot_20190706-092314_Minecraft.jpg I've been running around Minecraft like you usually do, killing tons of mobs for xp. However I noticed that every bow that dropped from a skeleton had full durability as if it had just been crafted. Also, if a drowned was holding a trident and it dropped when killed, it also had max durability (though tridents dropped by unequipped drowned still had reduced durability). As shown by the screen shot, I haven't killed a large amount of trident wielding drowned so there's a chance I'm not accurate where they're concerned.