In general terms, approximately 100,000 monarchs are tagged each year and the number of recoveries reported each year ranges from 1000-3000.
Over the five (5) monarch tagging seasons of 2001-2005 (Fall 2001-Spring 2006), 7697 recoveries of monarchs tagged during those seasons were reported to us. If we assume that 500,000 monarchs were tagged in that period, then the recovery rate would be 7697/500000 = 0.015394 or approximately 1.5%
If we include recovery reports after the Spring of 2006 (of those tagged during that same 5-season period) the recovery rate would be a bit higher, in the range of 1.5-2.0%.
We will have a more accurate number once we whip our databases into shape, but that is going to take money we just don't have right now so we can't give an estimate for when this might be completed.
Hope this helps!