Edit (or add if it does not exist) the following line:
<ProceduralDensity>0.5</ProceduralDensity>
You may replace the value by::
0.5 for "Infinite High"
0.35 for "Infinite Normal"
0.25 for "Infinite Low"
Delete the line for "Infinite None".
You may replace the value by::
0.5 for "Infinite High"
0.35 for "Infinite Normal"
0.25 for "Infinite Low"
Delete the line for "Infinite None".