Density of Micrometeoroids in Space

[GeeKay]

While it seems that some scientists/astronomers/pundits now have a fair idea about the average distribution of dust grains in outer space (one per million cubic metres, according to one source, ref. link below), I can find no such confident claims when it comes to the distribution of micrometeoroids in the interstellar medium - i.e. objects around 300 - 500 micrometers diameter (or wide). The silence here - if silence it is - intrigues me almost as much as my desire to know the answer. Maybe the answer lies in the future. Who knows? I don't, that's for sure

 

http://science.jrank.org/pages/3656/Interstellar-Matter.html