The notional steady level of noise exceeded for a specified percentage of the total measurement time. The value is usually found from the cumulative distribution table and so the number of sample bins used to collect the raw data in the instrument controls the resolution. For samples collected at 0.5 dB sample resolution the percentile level can only be displayed with a resolution of 0.5 dB. Typically an instrument will be able to calculate and display up to 5 LN% values but other values may be possible to obtain if the distribution table is available at download time using computer software.