It means the 84th, the 95th, the 97.5th and the 99.85th percentiles.
These are sample estimates. They estimate the values in the population for which 85%, 95%, etc, of the population values are less than the values. For example, if the 84th percentile is 12.3, that means that 84% of the population values are less than 12.3. If the 95th percentile is 15, that means that 95% of the population values are less than 15.
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