Breakdown of Grand Prix race participants

I've never seen a breakdown of USATF NE participants versus overall runners in each GP race and thought it might be interesting to figure it out. 

I was surprised that over 80% of the finishers at the 20k were USATF, that is pretty amazing.  The lowest USATF turnout percentage was the 1/2 marathon, which again wasn't a big surprise New Bedford probably gets that many GP runners even when it isn't in the GP!

I'm not sure why the turnout was so low in the marathon, maybe the conflict with the USATF NE XC?  Or maybe some stayed away since many titles were already settled before the race started?

Race	USATF finishers	Total finishers
5k	552	953	58%
13.1m	517	2469	21%
5m	380	679	56%
10m	378	1216	31%
20k	249	301	83%
10k	487	936	52%
26.2m	121	486	25%
	2684	7040	38%