New forms are available from the Record Claims – Procedures page.
trend-world-marathon-record
This Marathon Record Trend graph is from “Yes, there is a limit to athletic ability – physics” by Paul Savage, CSIRO – July 2012

For a graph showing the progression of male and female world athletic records in nine Olympic disciplines from 1900 to 2007 see Updates on improvement of human athletic performance – British Medical Bulletin – July 2008.