SawTroll
Information Collector
1999 week 36.
I am still learning some details, and what I posted when this thread was active wasn't quite correct. I have later learned from exemples that the change I thought was made for 2000 then actually happed some time in 1999, and the addition of a digit to the last part (behind week numbers) happened at the same time, not at an unknown time earlier.
The system adopted "some time" in 1999 is unchanged later, and still the one used.
More 1999 exemples will help narrow down when "some time" was.
It is narrowed down to about week 17 1999 by now.....