There have been ~1,250 ATGM launches since April 2014 (when the TOW got introduced.)
Figures are thanks to @yarinah1 on twitter.
Assuming 90 TOWs failed (VERY generous figure, and by failed I mean misfire/miss/target only damaged), and 300 TOWs were vs. Soft targets, 500 TOWs were launched against Tanks. 500 tanks vaporized within 2 years. This is not counting captured tanks, tanks destroyed by other means (RPGs, IEDs), and tanks that are not serviceable.
Here is other ATGMs:
My estimation, due to all the attrition suffered so far, SAA is down to 2,500 tanks from the 5,000 it had, and they definitely don't have crews for all of them.