At the height of the Clone Wars the HCS had tens of thousands of tanks in service. Since the reductions in size of the Clone Army the number has been reduced to about 19,000 - roughly half T-89F and T-55Z. Admiral Anderson has announced the Clone Army will form three more armoured brigades over the next three years. The number of tanks in service will rise to about 21,000.
These extra tanks will be T-55Z7s (aka ZDM3). The tank is already in production but the factory producing it will increase production early next year.
The Clone Army is also going to fund extra upgrades of T-89s to T-89FSU2 standard.