Since the last hardfork the debt ratio does not count the HBD balance in the DHF (in theory this went into effect on the previous upgrade but there was a bug in the code that was fixed this time around). So the price point where HBD is no longer 100% backd by the virtual supply is (at this moment) 27.5 cents per Hive.
We could still in theory create 10 million more HBD outside of the DHF if the price of Hive stays the same.