Solid number I don't know, I just CEOTP'd into Arty eff 15 April so FY 07/08 and there were quite a few Mars types also went (my former trade lost 8 of us on one coast alone). I know that all CBT Arms trades are in demand as is mars and pilot, as for the number of holes to be filled you're best off asking the recruiting centre or the BPSO.
edit to add I can check Tuesday when IO get back to work on a DIN machine and can get a look at the SIP from CFRG, unless of course anybody here is working over the weekend