Stats about the top 100 US races in 2011...

Running USA recently released stats about the top 100 timed races in the US and how things have changed over the last 11 years.

Number of timed races in the US from the top 100

The big change has been in the number of Half-Marathons. Back in 2000, there were a number of really big 5k races. This has fallen way back now with the Half-Marathon taking over.
(Note that this graph is for the top 100 races, it doesn't say that the number of 5k races has dropped.....only that they are a lot fewer now in the top 100)

Here are a few other facts....
1) From the top 100 US timed races, the number of finishers went from 922,500 in 2000 to 1,611,599 in 2011.......a 75% increase.
2) In 2011, Women accounted for 7.6 million finishers in US races (a record number) and represent the highest event field percentage ever reported (55%).
3) Some of the biggest races in the USA in 2011 were....
5K                    34,751E            Race for the Cure: DC (6,951 timed) (Washington, DC)
4 Mile               22,676              Pat’s Run 4.2 Mile (Tempe, AZ)
8K                    32,442              Bank of America Shamrock Shuffle (Chicago, IL)
10K                  55,077              Atlanta Journal-Constitution Peachtree Road Race (Atlanta, GA) – largest ever
12K                  51,303              Lilac Bloomsday Run (Spokane, WA)
10 Mile              25,244              Blue Cross Broad Street Run (Philadelphia, PA)
Half-Marathon   33,257              Zappos.com Rock ‘n’ Roll Las Vegas (Las Vegas, NV) – largest U.S. ever
Marathon          47,133              ING New York City Marathon (New York, NY) – largest ever

4) The largest race in the world in 2011 was the City2Surf 14k in Sydney, Australia which had 68,929 timed finishers.
5) In 2011, six Marathons in the world had more than 30,000 finishers – New York City, Chicago, London, Berlin, Tokyo and Paris.
6) For the first time, there were four half-marathons worldwide that had more than 30,000 finishers (Göteborg, Bupa Great North Run, Zappos.com Rock ‘n’ Roll Las Vegas and OneAmerica 500 Festival) plus a record eight half-marathons worldwide with more than 20,000 finishers, and last year, based on finishers, the United States had 14 of the top 20 half-marathons in the world.