The estimate of 18,000 fighters was based on intelligence estimates that al Qaeda trained at least 20,000 fighters in its training camps in Afghanistan before the United States and its allies ousted the Taliban regime. In the ensuing war on terror, some 2,000 al Qaeda fighters have been killed or captured, the survey said.
We're killing them off and they call it "revitalizing."
BTW, notice the date which they chose to use as a benchmark; October of 2001; I do believe that that would have meant that these horrible people trained on Bill Clinton's watch.
Yup, and I suspect many of the original al Qaeda "warriors" have decided to go home and stick to goat herding.