This is a chart for the HBD supply and savings starting from the Hive era, April 2020 till today.
It seems that we have around 3M to 4M always liquid HBD, with the exception of the spike back in October 2021 when the overall HBD supply increased a lot due to high HBD prices.
Curently at 8M HBD in savings and 3.7M liquid, around 70% of the HBD is in savings now.