More than three-quarters of all athletes competing at the World Championships in Athletics here have voluntarily submitted their blood samples, the international athletics governing body said Saturday, in a boost to the organization's large-scale anti-doping campaign. In a statement, the International Association of Athletics Federations (IAAF) said more than 1,400 of 1,945 athletes from 202 nations, or 75 percent of the total entry list at the biennial competition, have come to the drug testing center inside the athletes' village to give blood.