The number of staff an airline has does not reflect the amount of labour they use. I can take Sin Air for example. Engineers are all within a different company called SIAEC with HM employed by ST AERO. I doubt that they are reported in Singapore staff numbers.
Cathay is the same. Bugger all Engineers with Hkg Line and Heavy staff all employed by HAECO. They have a completely separate listing on the HK stock exchange and have their own annual reports even though they are also owned by the Swire group.
If you want to use the staff numbers from the airline annual reports, you may find that a number of airlines can run with a hand full of maintenance staff. It doesn't mean they don't incur the maintenance expense however.