Good thread.
To add some additional data, I went onto marathonguide.com and loaded the number of Boston qualifiers from the "top 30 Boston Qualifier marathons" in the US from 2003 - 2015.
A few points:
- "top 30 Boston Qualifier Marathons" = the 30 marathons with the most total qualifiers, not necessarily the highest % of qualifiers relative to # of finishers
- I removed the Boston Marathon itself from the numbers, as that seemed like double counting
- I concede this is only a 13 year data set. It would be interesting to take this back to the 70s and 80s, but this is all the data I saw
- I get that 'sub-elite' does not equal 'Boston qualifier', but I thought it was an interesting proxy to look at
- The data suggests a small rise in the total number of Boston capable runners over the past 13 years, but the % of runners who qualify remains steady with the exception of three historically good years from 2009 - 2011
Year # Finishers # Qualifiers % Qualifiers
2003 223,152 20,347 9.1%
2004 227,827 19,672 8.6%
2005 250,586 22,292 8.9%
2006 253,049 24,700 9.8%
2007 249,646 22,548 9.0%
2008 251,504 24,839 9.9%
2009 260,161 28,926 11.1%
2010 253,623 27,491 10.8%
2011 249,025 27,852 11.2%
2012 224,135 19,187 8.6%
2013 277,573 23,832 8.6%
2014 274,776 23,572 8.6%
2015 263,699 23,216 8.8%