I don't exactly know, but you have to take into account all the facts.\n\nFirst, some players have been told they should use performance-enhancing drugs by those they respect within the organization.\n\nSecondly, when players were extremely good because of performance-enhancing drugs, some players were forced to take them as well so they could keep up with that level of play.\n\nNext, for a period of time, these drugs were not strictly prohibited, so many players were using them.\n\nLastly, there are many people who have denied that they have used these kinds of drugs, like Rafael Palmeiro, but were really lying, and no one found out for a while.\n\nIn conclusion, I can't give you a precise number, but I would say a good portion of pro baseball players have used performance enhancing drugs - maybe 35%?