Unclear question. However, I inferred you are referring to page 58 of the article "This Week: Who is Responsible for Doping in Professional Team Sport".
Answer:
1. 63
2. 51. 6
3. Steroids aided performance
Step-by-step explanation:
1. We get the average annual home run record before steroid testing by summing the home run record 1998-2002 and divide by 5 years which = 315/5= 63.
2. We get the average annual home run record after testing began by summing the home run record 2003-2007 and divide by 5 years which = 258/5= 51.6
3. The data shows a decline of about 18% (51.6/63 * 100 - 100= -18.09%) in annual home runs after testing began, leading to a conclusion that steroids aided performance.