Seven years and still going!
This is an all time for HBD, formerly SBD (until March 2020) price.
This is the price that the blockchain values HBD when converting it to HIVE. Not the external market price for HBD.
We can notice the drop on two occasions. First at the end of 2018 that was short lived for a month, and then again at the end of 2019, that lasted for few months up until April 2020. The lowest HBD has dropped has been 60 cents and it has recovered from there.
From the Hive fork, HBD on chain price has never dropped bellow its peg.