The “percent <= and >” window reports what fraction of the sample is less than and greater than four sizes, which you enter into the window on the left side. With the distribution shown, 8.19 % of the sample’s particles, by particle count (“number”) are below 10.0 microns in size, and 91.7 % are between 10.0 and 50.0 microns.
The sample contained a few unusually large particles. These do not show up in the number distribution, but in the volume histogram they appear as spikes toward the high end. Even a single large particle can show up as a spike in the volume graph, if it represents a significant fraction of the total volume.
The Percents report shows that about 14 % of the total volume is represented by these few large outliers.