A large set of data collected by numerous WSR-88Ds was analyzed to estimate the percentage of tornadic mesocyclones. A total of 5322 mesocyclones satisfied the objective criteria used in the WSR-88D system; only 25% of these were associated with tornadoes. In terms of height of mesocyclone base, 15% of mid-altitude mesocyclones were tornadic, and roughly 40% of low-altitude mesocyclones (e.g., those with bases <=500 m above radar level) were tornadic. These results confirm that the percentages of tornadic mesocyclones, particularly with reference to mid- and low-altitude, are indeed lower than previously thought.