As an “adult onset” runner and marathoner, I found this article on RunnersWorld.com to be fascinating. It looks at the 25 most popular marathons in the United States for 5 different years, over a period of 5 decades (1972, 1982, 1992, 2002, and 2012).
Who would have guessed that the marathon with the second most finishers in 1972 would have been in Fairbanks, Alaska!!
Or that in 1972, the New York City Marathon only had 187 finishers!!