Thank you, it's at least 8 years old so I can't imagine that there are many left! 
There is a decent amount of singles left just not that many go up for sale. Do you have any other single bitbills or is this your only one?
FYI, there are 333 of the 1btc bitbills still in tact: https://bitcointalk.org/index.php?topic=3334918.msg50843287#msg50843287