Is there a way to check that simulation done and all particles is sleeping?

[mmortall]

I need somehow to know that all particles are in sleep state. Because I need to stop simulation then, save simulation mesh etc. 
For now I use just a timer, but I want to use some smart way to check simulation done. So basically I need to know a percent of perticles are in sleep state and if like 99% in sleep state then considering simulation done.

It there a way to do what I wan currently?