"...Anonymous surveys done after elite athletics events in 2011, in which 57% of competitors admitted doping compared to under 4% in WADA test results..." https://www.theguardian.com/sport/2017/aug/29/sport-doping-s...
"...In addition, of the 81 different riders who finished in the top-10 of the Tour de France during this period, 65% have been caught doping, admitted to blood doping, or have strong associations to doping and are suspected cheaters. ..." https://www.businessinsider.com/lance-armstrong-doping-tour-...
"...For a nearly year Serena Williams was allowed 'Therapeutic Use Exemptions' (TUEs) which involved LOTS of steroids. Date for use/Date given/Substance
Oct 2010 - Mar 2011/23 Dec/Hydromorphone Dec 2010/23 Dec/Oxycodone Nov 27-Dec 1 2010/23 Dec/Methylprednisolone 12-19 Mar 2014/13th Mar/Prednisone 21-30 Mar 2014/2 Apr/Prednisone 7-21 May 2014/8 May/Prednisone 10-17 Nov 2014/3 Dec/Prednisone, Oxycodone 5-10 June 2015/8 Jun/Prednisolone https://www.tennis.com/news/articles/tandon-a-closer-look-at...