Good Question:
they have it at 22.5 on S&P500 website.
http://www2.standardandpoors.com/portal/site/sp/en/us/page.topic/indices_500/2,3,2,2,0,0,0,0,0,1,11,0,0,0,0,0.html
I think it has to do with their methodology,
if you use operating 12ttm EPS
then 984.94/(sum of the most recent 4...