The legends on the main graphs appear to be wrong: According to the caption for Fig. 3, the blue curve should be 30-day plots, but the legend calls that 90 days. The legend doesn't make sense when you consider which numbers should be included in the others, e.g. that 0-day patches are also included in 30-day etc. Thus the green line is 0-day, the blue line is 30-day, the red line is 90-day, and the grey line is 180-day. MS has been around 60% 0-day +- 10% for much of the interval, except a dip to below 40% in most of 2004, and they are now up to almost 80% 0-day patches. The 90% 0-day patches in 2002 is impressive almost to the point of being suspicious. Apple has been climbing from 0% 0-day patches before 2003, managed to be above 60% for most of 2006, but fell to about 40% in 2007. For total patches within 180 days, MS has been in the 90% area most of the time, above 95% at the end of the study. Apple has been above 80% 180-day fixes most of the period, but only briefly above 90%.
Who wants to do the same thing for Linux?