"athletes whereabouts" program was put into place under the IAAF.
From 1997 to 2007 there was a sharp drop in the number of men and women running under 10 seconds and 11 seconds respectively. But since then, something remarkable happened. The number of men running under 10 seconds increased from 6 to 27 (so far this year) and women from 4 to 20 (so far this year). I've added a linear trend (in red) to each graph.
You don't have to run any fancy statistics to see that the world of sprinting is qualitatively different from 2008 to 2015 than it was from 1997 to 2007. What it is cannot be gleaned from the numbers alone, but it is interesting.
This post inspired by posts at track-stats.com and John Mulkeen. Data courtesy IAAF.