More than 3,000 samples were collected from nearly 2,000 athletes during the February Winter Olympics in Milan-Cortina, Italy, with no reported violations of anti-doping rules, the BBC reports. These are the first Winter Games since 1998 in Japan where no positive tests were recorded during the competition. In the years following the 2012 London Olympics, 31 medals were stripped, and an additional 46 were reallocated due to positive doping tests. The McLaren report, commissioned by the World Anti-Doping Agency, later determined that Russia operated a state-sponsored doping program from 2011 to 2015—a period covering the 2012 Summer Olympics and the 2014 Winter Olympics. However, the fact that there have been no positive tests so far does not mean there won't be any in the future. Athletes' samples are stored for 10 years to allow for retesting when new methods emerge. This means it may be too early to describe these Games as the "cleanest." One reason for the decrease in positive results is a significant increase in testing ahead of major competitions. The International Testing Agency confirmed that 92 percent of participants were tested at least once in the six months before the start of the Milan-Cortina Games, with Director General Benjamin Cohen describing it as "the most extensive program we have ever conducted."