80% chance of green, 18.50% chance of blue, 1% chance of purple, 0.50% chance of exotic. OR 89% chance of blue, 9% chance of purple, 2% chance of exotic would be excellent, since every 10 or so strikes you SHOULD see atleast one engram/item of purple or better quality. Just give bosses a drop table specific loot drops for each boss to encourage different strikes with role chances like this and people will enjoy strikes more. Thanks.