This image shows the global (from 65 degrees north latitude to 65 degrees
south latitude) monthly average total ozone amount for the time period 1979
through the end of 2001.  The green line shows the results from Nimbus-7 TOMS
instrument.  The red line shows the results from the Meteor-3 TOMS instrument.
The blue line shows the results from the Earth Probe TOMS instrument.