NarcoLeaks is an organization that has decided to dig into the statistics release by governments measuring the "success" of the drug war--which is generally limited to quantifying the amount of product captured and estimates of the impact on production. NarcoLeaks questions both of these.
From an article at the Borderland Beat, we learn that in 2011, the total of high quality cocaine seized that was 774 metric tons. Additional tonnage was lost due to raids on production facilities, smuggling vessels sunk, etc. However, that same year, world wide production of cocaine was supposedly only 700 metric tons. This begs the question of how more cocaine be seized than had been produced? The obvious answer is that the amounts seized are over inflated or the amount produced is underreported, or both.
My guess is that both is occurring because law enforcement is under pressure to show success on drug enforcement, it must show large numbers of seizures, but also that it is having an impact on production. It would be unacceptable if law enforcement had failed on both counts.