The amount of notes in circulation mainly dwindled during recent months.
Amount (left) and yield (right) of notes
As shown in the diagram, the amount and yield trends decreased simultaneously, showing liquidity problem facing banks.
The main function of notes issued by central bank is to absorb excess money supply from the open market and such a deep decline shows that there is no excess money in the bank system.
Once can now predict that the notes market may dip to zero in the context that banks have no money to buy notes.