Employing the well-established "Match" technique, we quantify polar stratospheric ozone loss during multiple Arctic and Antarctic winters, based on observations from the spaceborne Aura Microwave Limb Sounder (MLS) instrument. The dense MLS spatial coverage enables many more matches than is possible for balloon-based observations. Applying the same technique to MLS observations of the long-lived N2O molecule gives an measure of the impact of transport errors on our ozone loss estimates.