Surface height distribution for Jupiter's moon Io? The moon Io has around 100 mountains:

These structures average $6 {\rm\, km}$ in height and reach a maximum of ${\rm 17.5 \pm 1.5\, km}$

I am now looking for the overall histogram, i.e. elevation distribution of Io's surface and/or a hypsometric curve for Io.
References

JPL: Topography of Io
This blog by Butcher and Conwey on Geomorphology (or should we say io-morphology?) was a good starter. It seems usual to deal with the distribution of mountains and volcanos on Io. There are height maps (DEM) which give the distribution colour-coded. The closes to a hysometric curve found for Io is in this paper by White et al (2014) which gives a hypsometric curve where they exclude the volcanos in figure 9. 
Noteworthy might also be this poster by Wiliams et al with geological map but also a height distribution given single measurement &quot;points&quot; (where the points are areas of various size).