How can I interpret this solubility data? I'm currently trying to make incense paper.  I've been instructed to mix ethanol 90% with potassium nitrate ($\ce{KNO3}$).  As ethanol 90% is hard to get where I'm located I'm currently using methylated spirits (95% alcohol) as an alternative.  The $\ce{KNO3}$ however is insoluble with the this.  If I dissolve the $\ce{KNO3}$ in water first then add to the methylated spirits the solubility improves but it is still very cloudy.
I went onto http://periodic-table-of-elements.org/SOLUBILITY to see if there were any suggestions.  The page had the below results for $\ce{KNO3}$ solubility with ethanol: 


ethanol [$\ce{C2H5OH}$]: insoluble
ethanol [$\ce{C2H5OH}$] 50%: 3,7 (20°)
ethanol [$\ce{C2H5OH}$] 90%: 0,3 (20°)


I'm not sure what the 3,7 and 0,3 indicate though?  I'm not even sure what they refer to perhaps soluble parts per 1000 ?  If any one could help with what it means that would be great.  As you can guess I barely qualify as a hobbyist chemist.
Yes, the website is a little bit ambiguous. However, there is a clue in the colour legend. The solubilities are indicated in units of grams per 100 grams of water. (This is also a very common unit for expressing solubilities.) Therefore, a solubility of "$3.7$" means that $3.7~\mathrm{g}$ of $\ce{KNO3}$ dissolves in $100~\mathrm{g}$ of whatever solvent it is listed under. This interpretation is readily confirmed by checking the values against this Wikipedia page.

As for "$50\%$", my educated guess is that it refers to a mixture of $50\%$ ethanol and $50\%$ water.

And lastly "$20^\circ$" refers to $20~^\circ\mathrm{C}$.