One of the more minor disruptions of today’s horrific events at the Boston Marathon was that thousands of runners did not finish the race.  About 79% of those who could be expected to finish actually finished.  According to the estimates presented below, about 4,800 runners who could have finished did not because of the race cancellation:

Sources:  2013 Boston Marathon Data and 2012 Boston Marathon Data

Additional details after the jump

2012 Boston Marathon Stats

2013 Boston Marathon Stats