does it mean more than 95% of runners run at over 185 spm?
I'd tell that the explanation is rather unfortunate. The percentile means that 5% of runners run with cadence less that 153 spm, 5-29% with cadence less than 153-163 spm,... and 95% of runners run with cadence 183 spm or less (not more!). So again only the remaining 5% run with the cadence above 183. Otherwise the percentiles for individual zones would not add up to 100%.
On the other hand, according to the text, experienced and trained runners run with cadence over 180. So from the chart it is clear that the vaste majority of runners are "innexperienced" and run with the cadence lower than those 180 spm 
