Seriously I get like two or three a day farming but i get like 14 to 15 runes of War and Pride.
Here's a good way to know if something will drop rarely. Does it contain the games best or most sought after gear? Then it rarely drops. Bungie's RNG isn't really random where it counts. RoD drops the HC which is an awesome HC so it will be harder to get. Same way the Spare Rations never drops in Reckoning.