Quickly checked out the top 10 picks of each of the past 11 years to see how many turned out to be busts..the guys named below are obviously the ones I did not consider to be busts.
2000 Draft
3/10 (KMart, Miller, Crawford…Przybilla and Dooling are debatable) - 70% Bust
2001 Draft
5/10 (Chandler, Gasol, JRich, Battier, JJohnson) - 50% Bust
2002 Draft
6/10 (Yao, Dunleavy, Gooden, Nene, Amare, Butler) - 40% Bust
2003 Draft
7/10 (LBJ, Melo, Bosh, Wade, Kaman, Hinrich, Ford) - 30% Bust
2004 Draft
7/10 (Howard, Okafor, Gordon, Harris, Childress, Deng, Iguodala) - 30% Bust
2005 Draft
8/10 (Bogut, Marvin, Deron, Paul, Felton, CharlieV, Frye, Bynum) - 20% Bust
2006 Draft
6/10 (Bargnani, Aldridge, TThomas, Roy, Foye, Gay) - 40% Bust
2007 Draft
6/10 (Durant, Horford, Conley, Green, Noah, Hawes) - 40% bust
2008 Draft
9/10 (Rose, Beasley, Mayo, Westbrook, Love, Gallo, Gordon, Augustin, Lopez) - 10% Bust
2009 Draft
7/10 (Griffin, Harden, Evans, Flynn, Curry, DeRozan, Jennings) - 30% Bust {Rubio is an unknown}
2010 Draft
too early to tell
So an average of about 35% of top ten picks turn out to be busts.