Baseball, home runs, steroids

The top 500 individual single-seasons for home runs all time, summed per year, normalized to standard deviations (from the 1920-1994 period). The red lines are the years 1995 (the year after the strike) and 2007 (the first year of HGH testing). All of the years in this period are between 4 and 8 standard deviations above the mean (note that the data are slightly non-gaussian so the mean and stddev are slightly inaccurate).