It's evident that it refers to the submarine without additional upgrades.

With the "virgin" submarine, I assure you that as soon as you've jumped over 8 knots at periscope depth, you're already cavitating as if the propeller were a cocaine-fueled underwater rave.

This list may be inaccurate.
I'm not sure if a new propeller or "own ship quieting" does have any effect on cavitation, but with all improvements e.g. 10 knots at 58 feet depth are no issue as well and similar and higher deviations from this table at other depths. So what is this table actually based on?