PL/SQL in 23th in TIOBE Index for October 2010.
A drop of 10 places in one year!
Of course that index is not very accurate, but even so I would not expect a drop like this one, specially with PL/SQL Challenge that was created this year (ok...it's not a very index (meaning Google, etc.) friendly site), and the APEX grow.
I think that one reason for that is that with APEX the PL/SQL community use APEX as a label/post and not mention PL/SQL when writing/posting code for it.