Really? I havent seen that math. For that to be true, the number of collisions would have to be rising faster than the rate at which we put stuff up there. Natural sources would cause a steady increase (more stuff launched, more exposed to natural impacts) whereas not-natural junk impacts should increase at a rate higher than exposure (compound increased exposure with increased risk from more objects). All i have seen are studies saying that the number of impacts is increasing, not that they are accellerating faster than launch rates.