Unpowered SSD data retention time is quite long for SSDs that have not been used previously
The unpowered data retention time diminishes quickly with the number of times that the sectors used for storage have been written previously.
That is why the retention time of 1 year that is guaranteed for consumer SSDs is specified for a SSD that has been written with the maximum amount of data specified by the vendor.
Moreover, the retention time decreases quickly with increasing ambient temperature. It can be much longer in a fridge than in a place with tropical climate.
So that test proves nothing, because it has not been done in standard conditions. For a retention test, you must know how many TB of data have been written on the SSD before the test and which was the storage temperature.
If you have never written before the SSD and you store it in a cold place, it is likely that the retention time will be of many years instead of the guaranteed 1 year. Otherwise, it is reckless to hope for more than 1 year.
